pba,
Quite right, in the F3, most a/c have the shoulder mounting fuel contacts disabled. Actually, it probably only flew in that fit once for the testing purposes! I've certainly never flown or even seen it.
I never quite understood the GRs doing 3 bag fit tho, surely 2x 2250L tanks are better than 3x 1500L tanks? (Drag?) Perhaps a GR chap might comment.
Regards, and thanks for the correction,
Advo