It's a well known issue that Van's rivet callouts are sometimes a little short. Don't know if Van's just made a mistake or didn't account for any primer, or if the rivet call out is a suggested starting point or what. Whatever the case, I would suggest that you adjust to use the rivet that results in the proper sized "shop" head. Use a rivet guage until your eye gets callibrated. Once you get the rivet size and eyeball zero'd in, thing will go together quick.
Where in BC are you located?
Bevan
Abbotsford