As for tweeking I unfortunately mean adding cards you would not get from certain sets for example an engine upgrade that only comes in the falcon so lets ignore that.
As to 3 B-wing lists I've yet to try any or play against any but the cookie cutter looks good, I like the fact that they are dagger squadron.
My only thoughts in the back of my mind have always been to try to find lists that let you buy ships that in turn give you many squad options in the future with the same ships.
Not sure if 3 B-wings does that for you, or an A, Y and B either as you may not use the A-wing that much but will use push the limit and the Y-wing.
That said I hear the Y-wing is out of stock so POO to that idea anyway.
My two cents, Stick with squad 1 unless you find your friends list is killing everyone including practised flyers.
Assuming he will be running it before you order your ships.