There is a very good post on silphroad reddit that I've refgerenced twice yesterday here(one in a thread related to pinsir, one I forgot where) where a lvl 40 trainer explained quite in detail how he soloed lvl 3 raids (execept Flareon and jolteon) with lvl 30 pokemons.
Search for it if you will, is full of very good advices. I almost regret that I went all in with my golems :).
Basically its ok to have multiples at level 30, with ideal ir very good combos, at least for now.
Here it is solo raid 3 with mons under lvl 30