Getting back to the original question, and in particular your concern about your weight, no you are not too heavy. Take a look at this guy as an example - very famous UK sailor, very big boy, sails small gear & freestyles like a ballet dancer, sails big gear & speed sails like a gorilla!
www.windsurf.co.uk/featured/whitey-10-0/2/Almost all the guys going for out and out speed (on flat water) wear lead lots of it 20KG is not unusual , and in spite of what some people on here are claiming rig big cambered sails on small boards with small fins with massive amounts of downhaul. Weight is an advantage and mast bend etc etc due to weight does not seem to slow them up!
Freestyle riders sail medium sized boards with small fins with the smallest simplest sails that they can to get them plaining for short bursts.
Slalom type riders sail as big a sail as they can hold on to riding medium sized boards with as big a fin as they need to stop spin out on chop.
Freeride riders (90% of us if we are honest) ride forgiving yet reasonably high performance sails on slightly bigger boards that are slightly more user friendly (up haul?) with biggish fins (maybe more raked for gybing help).
I got rid of all my slalom type boards and cambered sails a few years ago as I found that gear awesome 10-20% of the time when things clicked, good wind, flat water, consistency etc etc. However most days we sail the wind backs and veers go's up or down by 5-10 knots and the water is choppy or small waves. I was hating sailing except for that 10-20% of the time, now Im smiling every sail. Yes guys pass me by going faster but I also sloggers past them in the water waiting for the gusts, or at the gybe where I've bogged round in a lull when they are in the drink etc etc!
Its not your size nor your ability its gear selection, only my opinion, but you have selected good gear for your size and locations, now you just need to rig it as recommended to get used to it before you tweek it , and get out there as much as possible.
Modern stance is different to 30 years ago and if I work out the exact subtlety of it Ill let you know!
Remember what they say- advise is unforgivable!