I haven't actually done it myself,... just read about it. I'm thinking you use the hexed part on each cam shaft instead of the cam bolts. The wrenches are kinda in the way on those bolts anyway. I haven't even seen the hexed spot on the cams,... I learned about them after doing the job. I think you just put two wrenches on the hexes of the cams and put a zip tie connecting the boxed ends together (I haven't even seen a picture of this) and that at least hold the two so they both have to move together,... my guess is there would be enough friction to the movement that it would hold still. I noticed the Exhaust valve lobe on #1 cylinder is just starting to push on the lifter so it springs back from its timing position under a bit of tension.
I think the wire on the spring is a great idea as well (I did do that) because it helps prevent over stretching the spring. That spring is always active,.. some timing belt systems just add preload to the tensioner wheel then the wheel is locked down when you tighten it. Our tensioner wheel is always moving.
One guy mentioned to put some paint marks on the belt and all three gears. If you get it all on again and it's off by a tooth again,.. put a paint mark starting at the crank where the belt is touching the gear (mark the gear and belt tooth) and the timing mark is lined up. Then mark the two cam gears the same way but mark the tooth of the belt where it Should be, not where it's wrong, that way on your next attempt, you'll know if it's the right tooth (especially on the exhaust gear). There's so much slack until it's on, you don't know if it's right until you spin it a few times.
I hope this helps,... I remember having to take about five smoke breaks doing it,.. I was ready to take a hammer to everything. Remember I was holding the the cam gear wrench with my elbow while using both hand to feed the belt on,... what a freakin challenge,... it's a good thing I'm flexible.