Tonight on my way home from work my Cosworth developed a misfire over 1.2 bar in 5th gear Boosts up to 1.2 bar perfectly but once it gets there is starts to misfire and hold back so I backed off

When I got home I took the plugs out and they look good but the gaps are slightly all over the place & I don't know what they should be gapped at and can't get hold of anyone at MSD at the moment. The gaps are currently between .60 and .75mm and the car is a stage 3 on one of Stu's chips.

Anyone know roughly what the gaps could be or what else might be causing it?

Thanks