A-B-C-D lights double bonus, and spinners for 100 points. Light them via in lanes, stand ups, and rollovers.
Unless you tilt your bonus, hitting a target for 500+1000 bonus is a better deal than trying to get a lit spinner to spin 15 times.
A and D can be lit on the spinner lanes as well as the targets below them, so if you need the letter the spinners are usually a safer go.
Try to collect 2 letters on your plunge - one of the B/C rollovers and the lane of a different letter.