well, something that i should have asked before patreoning, and example of an icon sketch/telegram sticker (joind that tier due to limited slots ;3)

but something to keep in mind would also be to charge upfront instead of on the 1st of the following month. (joined today, but won't be billed until Oct 1st)

and i suggest that because people will eventually join your patreon just to get the HQ files to share.

I usually do chibi style stickers like this
https://t.me/addstickers/Xuan_N

or can do this style if you want to :P
https://t.me/addstickers/xuan_sirius


and can be NSFW stickers >w>+


I don't have any icon sketch so far ;3; but there are some coloed sketch examples, should be the similar quality but more detailed .
https://www.furaffinity.net/view/36259795/
https://www.furaffinity.net/view/36475083/

Few thoughts 1) look into other services as well like subscribestar and whatnot. Patreon is doing some questionable things that might impact you.
2) commission slots are cool but if you do decide to do them, you might want to consider limiting them so you don't get potentially swamped and cycle the people in the tier so you don't have 1-2 people locking you down for long times.
3) maybe offer pin ups choices taken from Patreon members? Like their actual fursonas as opposed to whatever pop culture furry they want to see. (Optional for folk to include their OCS in the drawing pool)

With tier 4 being the highest priced (and is limited to 5 slots), it makes sense to include their character(s) in the pin up pool as an added award for early patreons (assuming in the future it will always be full). Usually most art patreons try to make the art rewards equivalent to the tier price but discounted.

Right now if I'm able to claim a reward it would most likely be the sketch as 50 dollars for 1 telegram sticker is a bit much ( could be either 1 full/half body without background sketch or 2-3 stickers), but at the same time its common for limited tiers to be set that way so that the artist isn't loosing money. As your current prices are 150 for a sketch and offering 1 randomly to the 50$ tier is ideal.

I also see the concern of only the same few people claiming all available commission slots in the future

Say there's 10 slots, all t4 peeps take one, the remaining 5 slots get taken by the next patreon tiers. And if someone wanted to commission they would have to be patreoned or get lucky that slots arnt all taken up before they are open to the public

Well moreso the top tier commissioners just never leave. I've seen some artists who have a commission slot that the same few people have had for over a year. So even lower tier Patrons can't get a commission. Let alone the random public.

I'm planning to do more than 10 slots in the future, so gonna be at least half of the slots left even if everyone in tier 4 grab a commission slots ^ ^;