IMO i'd start the patreon before the release but have a per release payment schedule for the first few updates as a show of good faith, with a rider of no more than one update per month(no payment button abuse) and no charges for bugfixes.
As for update size, that is tough to say, assuming daz/ren'py as standard a lot of the better devs here operate on X 100's per update, say 300 isn't unfair for a well established dev, though that would be very high for a beginner. Simply it depends on your medium and xpectation, how many animations if any, not to mention gameplay time per update. You don't need a huge number of renders if the quality is good and the gameplay time isn't very short, not that you should drag it out for ever either.
It should also be noted that this is without mentioning the style of the game, a visual novel needs more renders than a sandbox or a game with a more direct gameplay loop like a brawler or standard RPG as the latter especially has a lot of other things that are going on than just the renders.
My personal choice is good renders over lots of renders, and animations have to be very fluid to be worth more than good stills. It's not just about render number but content quality.
PS: for the love of god don't start something as long as superpowered for your first game, let other people make mistakes for you.