How much does stretching con rods increase cr,
 

I understand how it works, but how much can you get on a 3.2 rod. 1/2 a point or more?

I wouldn't bother. If say, the factory deck height is 1.2mm (just picking a number out of the air) and a safe deck height is ~1mm you can only stretch the rods .2mm. Hardly worth it when you'll get that much when you clean up the case spigots (decking the case).
-Chris

Chris probably knows more than I so consider this me thinking out loud. Are you not limited in droping the spigots heigth by the chain? How much can you play with this? Isn't also the same as simply reducing the base shims if any present?

You are suggesting an offset bore of the small end bushing, correct? How much could you deck the heads as you'd do in a typical engine (which obviously, again effects chain length)? How much room do we have to play with here in the typical chain tensioning devices?

I've thought about all the ways to increase compression without changing pistons, but I would think that shrinking the motor can cause alignment problems with the intake Maybe someone can tell me if there are any other viable options.