Surfing Waves

i want to get a fish really soon because its summer and im bored of riding longboards and i and to actually be able to turn again. i ride a 5'8 x 17.5 x 2 and im 5'4/5'5 and 120/125lbs i was thinking about a 5'4 lost round nose quad or buying a used 5'6 twin fin from a friend any suggestions on sizes or brand are welcome(it doesnt matter if its a twin or quad im cool with either)

quad is fast, but then it turns funny...

I'm using a firewire quadflex, i bury the board most of the time when trying to do bottom turn...