How many dratini is too many?

I found voltorb flip really fun and before I even realized last night I had beat level 8. I grabbed 2 but I can still go back and get 2 more. Should I go back?How many is too many? And who do you drop?

My thought is 2 is good maybe 3. I wouldn't mind rolling 3 dragonite, amphoros, tyranitar, charizard. Or else 2 dragonite, amphoros, charizard, 2 tyranitar.

When I get the chance Larvitar will be caught as it was my favorite from gen 2. Also quilava will be switched out for charmander. So I may roll partial party moving forward just to increase the chances of them becoming a dragonite quicker.