Adjustable Cam Sprockets???

[Duk]

On my excessively large list of things to do is to add an extra idler for the cam belt (not impressed by less than 25% belt wrap!). Now given that there is much possibility for cam timing to be out a few degrees with such an addition plus any machining that has been done to the heads, I have figured it would be a good idea to have my cam sprockets adjustable to get the cam timing spot on.
*I am still needing to get my hands on the correct valve lift to crankshaft angle info for the Motronic engine, too.

Is there anybody who is prepared to share information on doing this?

The few photo's I've seen have been from Richard Jemmison/Alfa7 on the Alfa BB. His approach seams to be a bit more involved than what you'll see for typical adjustable cam sprockets, partly because of the 3 piece design of the sprockets.

What I was thinking was to weld up the 2 larger, outer round holes in the front hub, remove the dowel (it's in the right spot for 1 of the new bolts) and use 6 bolts (bloody 7mm bolts  ) instead of 3, evenly around the same pcd as the original 3 but have radiussed slots to allow for a 10* or so movement, either advance or retard.

Constructive thoughts and/or opinions?