I'd suggest using a #1 or #2 lite wire Aberdeen ... even a #4 would be fine. Yes, you can hook the minnow thru the back, just under the dorsal fin. That'll work just fine. You can also hook the minnow thru the eye socket, behind the eyeballs .... in the tail ... or under the chin & up between the nostrils. All are perfectly good ways to hook a minnow, if you're going to be stationary. If you're going to be moving around any (drifting, slow trolling) then you'll want to hook them thru the eye socket or under the chin.
... luck2ya ... cp