But really, i only signed it on the 10th - I didn't email it til the next day (no scanner access - library closed)....and they won't get their post til Monday, so yeah - I don't know to what extent one can fix on the moment - there's so many stages to selling a house it's hard to know which to focus on.

There are going to be a lot of moments you will over-analyze and things beyond your control. I normally assume the initiation of the beginning of something is the intention, and is what's likely most important. There will be other moments to look at, such as the time of agreeing to an offer, closing, etc. I remember when I bought my house I was so worried because I closed on a besieged Moon. However, when looking at my natal, I can clearly see when I put in the offer is a significant life event. That was my intention to move forward. I could have even analyzed when I "met" the place, or first saw it online. The moments you could over-analyze are endless...

Tbh, the moment you submit it might be most important though. That's when you officially decide and I always look at that for things like job interviews and contracts, etc. However, I'm not going to tell anyone when the intention began, they should know via their own energy committed to the event. To me it is equivalent to other forms of divination, like spell work. The moment you officially begin the spell is the intention, not collection of materials, etc. Its's when the spell has begun.

Personally, I think the last day of Venus retrograde isn’t as shaky as the middle of it, but if you’re worried, waiting a few days for it to finish won’t hurt.