House rules can be different for each and every battle. You are right however that some of them are more common than others. Grumbler is right - there was a time while back when people seemed to spend more time on pre-game agreements than the game itself. I switched to stock scenarios then and am still happy about that.
It all depends on what you expect really from the game. After you play 50 or 100 battles you will be able to tell what you like the best - historical forces, all-out battles or else. And then you start thinking about the rules which can give you the type of game you want.
Most people here just try to play more or less reasonable battles and those 2 or 3 house rules usually are enough.
I personally dont think pre-bombardment in meeting engagements is realistic (and usually dont see it in my battles) but wouldnt bitch if my opp does that unless it was clearly stated otherwise.
And for those few purchase battles I still play every now and then I usually say - Lets buy reasonably historical forces, as I hate to count if I have 1 gun above the limit or not.
If you are looking for good refference how historical buy shoud be alike check this article by Steel Good. It is a good start point.
https://www.theblitz.club/articles/strat...php?id=111