I've got both kits. One thing I would recommend is tapping all the holes to the bottom. Most of the holes are very shallow tapped. As far as what size head studs mine was a hybred bas.tard of both sizes, M8 1.00 in the block and M8 1.25 on the head end. I got the M8 1.00. When I tried to screw in the stud it would not go in the hole, instead of being for a M8 was more like for a M7.9, just a little too small. I figure spec tolerances are pretty loose there in China
When tapping the hole use a greasey type of lube so the chips get stuck in the grease and don't fall off in the motor.
Buy and use a tube of Blue Locktite. Locktite won't work on the exhaust studs, too hot. Just make sure you botton out the exhaust stud. Tightening up a too-shallow stud is what pulls the threads right out of the hole.