I found a 3d printed one online that I had to try out, but your design looks way better, might need to try making my own. The 3d printed one works well enough, but I had to file down several edges for more play so they would slot together when the gears were under tension. Seems like the crank gear based one would be much easier to work with, especially trying to make small adjustments before reinstalling the belt. La-Z-Link https://www.jackflashautorepair.com/jackflash3d/p/vg30dett-camshaft-gear-tdc-locks