at your height and weight & the size of your regular hp thruster I'm surprised you can turn a 6'0 Flyer at all! those boards pack the beef and have a hard rail.
When I first got one I was lucky b/c my friend had purchased one before and his mistake saved me money. We'd been riding SharpEye Gliders 6'2" or 6'3" and 19.25 or 19.5 (we're both about 6' and 185ish) he bought a 6'2" Flyer and couldn't turn it for his life- it locked on a line and wouldn't let go- he took the hit and traded down an inch and I got a 6'1" myself but later realized a 6'0" was ideal. The Flyers and the M4 I had pack more foam than anyother board I've ridden & when I ordered my current Hammish Graham SuperStixs I went to small (6'0" b19.25) and need to return to the SharpEye type dimensions.
The guys I know your size would ride a 5'10" Flyer at the biggest- especially in the better CA " small" surf which is a standout day for us.
All the Flyers are Flyer F models- it was a redesign of the original Flyer many years ago (like 10). The website may say quad Flyers are custom only but for a while a few years ago they were pumping them out stock quite a bit my local shop still has one on the rack.