if you know how to repair a board ie: fibre glass cloth and resin etc..... you can strengthen it yourself..........it will never be your "paddle in" board ever again but it will work for what you want.

If you are riding with straps just strengthern where they fit/plug and around the foot area,,......... if you ride strapless then there is not much point unless you cloth and glass the whole top and then it will weight a lot. and better off done by a professional.

Without added strength Just avoid smashing into the lip when heading out into the break or you will probably break or crease the nose.

Koma, I'd steer away from the cheap epoxy board option. They're too fragile. Even the smallest fracture & it will suck in water like you wouldn't believe. Styrene cores are an open cell. It's almost like a hollow board. Repairs are more difficult because the skin is very thin & the board has to be at a stable temperature or cooling or the expanding air inside will be blowing bubbles out while you're doing your repair. Traditional boards are so much easier to live with, even if they do suffer a bit of damage.
I'm 75kg & my 6'2" x 18 3/4 tends a bit more towards the light wind end.
cheers Col

@ koma 'the highjacker' most people kite a board a little shorter than they would paddle. 2" taller than you seems dumb and too long to me.

@ graceful. I recently worked with a mate who had some glassing experience. We beefed up a few boards he got real real real cheap. I don't have a surfing background other than kiting and due to my extreme strength, power and psycho cool moves (not my lack of skill..) I have snapped a few regular surfboards quite quickly.

we put an extra layer of glass on the bottom overlapping the rails, some strips on top running most of the length of the stringer and then a layer over the whole top re overlapping the rails.

It now weighs approximately 10 tonnes but is sweet as for kiting. Buying all the gear to do it yourself makes for a good project but it is toxic stinky itchy crap and takes hours of labour to sand neatly if you are hoping for a finish like a board from the shops.

Im glad i did mine but your idea of getting a surfboard maker/ repairer to do it may be a better alternative imo.

if you end up doing it yourself and haven't done glassing before.. get the mix right. do it quickly and with confidence. remember that strength comes from the glass and weight comes from the resin, so squash as much out as possible.

re reading your post i guess my answer is possibly no help. hahaha sorry. might help someone i spose.