I am thinking of fixing the dash panel I have made to the scuttle using counter sunk head screws. This would mean that I need to counter sink the fibreglass scuttle panel accurately about twenty times. Never having counter sunk fibreglass before I was just wondering if I was asking too much?

You will weaken it.
If anything you should use domeheads with load spreading washers

I think you would find it would chip. I am going to use dome heads instead. Have you got an offcut or non visible bit you can try it out on?

HI At work i use a wood counter sunk bit the type with lots of cutting blades
Jacko

Really not a good idea you will just end up with crack running from the holes, in fact any screwed/bolted fixing used on GRP should use large penny washers.

As above...
AND - you won't/don't need about 20 screws to hold it in place. (I used 8 and it's more than enough) 7 would be a fine number...

Steve

I used 13 4 mm hex button heads.

Decided on M5 dome headed screws in the end. Have already drilled the holes so I had no option there.

Thanks for the help