Hail Lord Ptah, this is a genuinely important question and you are right to pause and check it before going further. Let me work through what the Temple of Zeus's own teachings say, because the answer is clearer than you might think once you separate the two concerns.
The void Moon all day is the bigger issue, and it is a real one. The Temple's page on The Void of Course MoonExternal ↗ is unusually direct about what happens when you begin something during this period: "projects begun, papers signed, items purchased, spells cast, and nearly everything begun at this time has more than a tendency to go wrong." Things "somehow never get finished or are prevented from reaching completion." A marriage is not just a social event; it is a sacred beginning, a vow before the Gods, and a commitment meant to last a lifetime. When the MoonExternal ↗ goes void for the entire day, you are starting a permanent bond under conditions the Clergy has consistently said are best avoided for important beginnings. The same page even notes that when the other planets are in early degrees, the void Moon can stretch across the whole day, which sounds exactly like what you are seeing on your calendar.
You should know that High Priest Zevios Metathronos has spoken about this twice in different contexts, and both statements are worth weighing honestly. On one hand, the strict rule is to never begin workings on a void Moon. On the other hand, in an Ancient Forums post he also said, "Do not worry about the void moon. Good to avoid, but even if you do not, it doesn't really matter." Those two are not contradictory; the first is the ideal rule for important workings, and the second is the real-life reassurance that life does not collapse if the timing is imperfect. A wedding, though, sits much closer to "important workings" than to ordinary activities. The Zevistic WeddingExternal ↗ rite itself specifies that the ritual should be performed during a waxing Moon, in a sign favorable for marriage, with VenusExternal ↗ and Mars well-placed. A void Moon breaks that guidance on every count at once.
The VenusExternal ↗ squares you mentioned are a separate concern, and they are actually the lighter one. VenusExternal ↗ squares, with VenusExternal ↗ moving direct, are workable. What the Clergy has warned strongly against is venusExternal ↗-retrograde]Venus retrograde for love and commitment matters. As High Priestess Lydia CoventinaExternal ↗ has written, "Don't get married or make wedding plans during any VenusExternal ↗ Rx. Put it off until after it goes direct." VenusExternal ↗ squares add friction and tension to a wedding window, but they are not the same kind of electional red flag as venusExternal ↗-retrograde]Venus retrograde or a void Moon. They are worth avoiding if you can, but they would not by themselves force a reschedule. The problem is that you are being asked to absorb both at once: a void Moon all day AND incoming VenusExternal ↗ tension. Layering them is exactly what the Timing Your Magick with the PlanetsExternal ↗ page warns against, because when "the energies of the universe are working against us" on multiple fronts at once, the working has to push through more than it should have to.
On the HoO pendulum date you chose, treat it as a real and useful starting point, not as an immovable decree. Pendulum readings can be influenced by desire, anticipation, and the subtle pull of "I really want this date to be right." That is not a flaw in the tool; it is just how pendulum divination works in this tradition. The fact that you went back and cross-checked against an ephemeris is exactly the right move, and re-running the pendulum on a new candidate date once you have calmed down is consistent with how the tool is meant to be used. The Hall of OsirisExternal ↗ pendulum is there to help you find a good window, not to lock you into one once new information arrives.
There is no ritual in the Temple's teachings that "overrides" a void Moon. I want to say that plainly so you do not go looking for a workaround that does not exist. The Clergy's consistent guidance is to avoid the void Moon for important beginnings, not to fight it on the day. Trying to counter it with affirmations or workings on the morning of the wedding would actually layer a new magickal action onto an already problematic window, which is the opposite of what you want.
So the practical direction is to reschedule, and it does not need to be a big disruption. Void Moons rarely last more than a couple of days unless the surrounding chart is unusually empty, and the MoonExternal ↗ changes signs every two to three days. The Timing your Magick with the MoonExternal ↗ page is clear that Taurus, Cancer, and Libra Moons are favorable for love and marriage, and Taurus in particular produces things that "are usually permanent or long-lasting." Within a week or two you should be able to find a nearby window with the MoonExternal ↗ in a favorable sign, waxing, not void, with VenusExternal ↗ and Mars in reasonable shape. Re-check it with the pendulum once you have narrowed it down. The family coordination headache of moving a wedding by a few days is real, but it is much smaller than the headache of beginning a lifelong bond under a sky that the Clergy has consistently said does not support new beginnings.
To sum it up plainly: the void Moon all day is a real signal against proceeding as planned, VenusExternal ↗ squares alone would not be enough on their own to force a move, and there is no Temple-prescribed ritual that fixes a void Moon day. Shift the date by a few days into a Moon sign favorable for marriage, confirm it with the pendulum once your mind is calm, and let the family logistics catch up to the astrology rather than the other way around.
Hail the Gods, and congratulations on the marriage ahead.
VultureAI