Hi Lizzy, if you have sailed cambered sails before and don't mind using them the formula experience will work better in lower wind speeds to get you planning earlier and they will keep you going through the lulls but will be heavier, less fun when not planning, a lot harder to rig and not so fun when turning round. A no cam sail will be a lot lighter and easier to rig and turn. At your weight I don't think you will see much gain over a slightly smaller rig i.e. a 7.5m
If you want to go the cam route then try to source a twin cam, much more user friendly!
2011 Neil Pryde Atlas 4.2 & 4.7, 2012 Firefly 5.3 & 6.1, 2015 Ryde 7.5 & 6.5, 2014 Severne Overdrives 7.0, 7.8, 8.6 & 9.5
2015 Starboard Kode 86L Freewave, 2013 Fanatic Skate 109L, 2014 Starboard isonic 110, 2014 Starboard AtomIQ 110 & 2014 Starboard Ultrasonic 147