Beernutz I am not saying the start pin is good or bad. But if I were starting mains with flying clamps I would run in the two center mains (1LM and 1RM.) use the tail on the left side to start 2LM and clamp the two left mains outside the frame. This leaves a long loop on the outside of the clamp for pull tension on the left main. Tension thre right mains (one at a time) and use the other flying clamp to hold. Then tension 6 left mains, finish the right, then finish the left. That way your clamps are never in the way of each other, and you don't need any special tools.
I would like to apologize to anyone I have not offended. Please be patient I will get to you shortly.