Ok then, so lets just say for the sake of argument, I decide to convert to a fixed idler. How much clearance do you think will be good between the cam gear and idler and the crank gear and idler? In other words, WHERE would you mount the idler?
You can mount the idler gear on either side of the crank and cam gears. It won't matter. The idler always has to turn in the opposite direction of the crank and cam gears so you don't have to turn the cam in reverse direction like you would with a 2 gear drive.
I'd mount it where you have the most room to make it fit. I set the lash with a dial indicator. I keep the lash between .002-.004 and let it run. You can also set the clearance with some magazine stock. Set the idler so it just tears the paper as it moves through the gears. Either way you'll be golden.