Spent about 1 hour drilling the holes in the 668 roll bar spacers.
But I think there's a problem.
Despite carefull measurement from the top, the hole the 921B canopy deck is too close to the longerons. If these are drilled out the proper size, the longerons will get nicked. That can't be good. Need to ask Van's about this, and proceed with something else. I may get to do the 668 spacers over again.