this is what I do, everyone's got different Ideas.
I troll squid bars @ 5 kts or a little better,sometimes a hair slower depending on sea conditions.
I know guys use them and they are popular in some parts ,but I've never had anything touch a cedar plug. and not from lack of trying.
there's nothing wrong with running a GM12 to 15 ft behind a bird. I like to rig them in threes 2 -9" in front of a 12" with a big bird up front. (I make my own out of cedar with aluminum wings. they're about a foot long) I run the 12" bait ,with the hook, about 10-12 ft back from the last 9".
speed has alot to do with what your running.squid bars, and birds and gm's are made to be run at different speeds in my opinion. gm's and birds are run a little faster.
my best days have been running three squid bars. sometimes I'll run something small ,close,I've taken a few fish on tuna clones run about 25-30ft off the transom. hope this at least gets you started ,there are a million variables.
It will be all right in the end,if it is not all right it is not yet the end.