I spent an hour at the hangar today, after work, finishing off the top engine cowl fasteners. Pictures below show the end result.
Although I have a very neat fit of the top cowl against the firewall, I think I'm going to need to sand the cowl edge back a little. I realised I'll need a very small gap to allow for final painting.
I'm also not happy with the uneven gap around the spinner. The gap is wider at the bottom edge of the cowl than it is at the top centre, and looks very unsightly. I sent a message off to Vans about this and they say it's not uncommon. They recommend fitting the bottom cowl, then building up with foam and fibreglass to make the gap even all the way round. Apparently this is what other builders have done.