i got two boards both with handles added.
one i used a strip of leather from a belt and it goes from one foot strap to the other and the footstrap screws simply go through each end of the leather it's a bit tacky (o.k. very tacky

)not that i'm in it for prestige. I don't even wear boardies over my wettie



but anyway that does the job without damaging the board. Not great for board-off manouvres though.
my other board has just got some shallow holes drilled into it and then some stainless bolts screwed into that. They will screw straight into the board if they are slightly larger than the hole that waqs drilled for them. much the same as bolts/screws into fins except you need to be very careful getting the right depth. I have seen boards where the screw/bolt was too long and after a while you will find bumps beginning to form on the bottom of the board. not good form.