Mmm... what MIGHT be of interest would be use of a set of solid lifters from another manufacturer that DID incorporate bucket and shim type valve clearance adjustment. Some component spec checking in the EP catalogues might be of use here?
I think the normal swap-for-clearance-adjustment T5/ T6 lifters would be perfectly fine for normal use, but less so for a regularly worked on competition type motor. I wouldn't want to get into altering valve lengths for adjustment (unless that was purely to allow for use a bigger cam base circle diameter) for a few reasons, not least that it would be a one-time adjustment and in use the clearances are always going to get LARGER with use.
The valve guides could either be changed or fitted with something like K-Line inserts to allow use of thinner stem valves while at the same time removing any wear in them.
In honesty, the beauty of using one of these motors at lower boost levels and rpm limits to me is that the vast majority of stock components can be retained to keep costs down while still giving good results and reliability If something then does fail seroiusly it isn't soul destroying or bank breaking, and most service parts are common, readily available and inexpensive. If I wanted to be throwing large sums of money at an engine in the pursuit of a lot more power I would probably have started off somewhere else.
This is exactly the kind of thing I'm trying to avoid by using a whiteblock motor in the first place....
For what I want then, a modified stock whiteblock head will get the job done. Even the obvious shortfalls in the block and bottom end design can be disregarded at slightly lower outputs and levels of heat, pressure and reciprocating component loading. I am a little surprised at how fast these motors are being revved without issue in fairly stock form by some people though.... all to the good.
It is a shame that the T6 cam (if it does have a larger base circle diameter) isn't quite so easy to drop into a normal whiteblock head. Reprofiling a pair would have been much cheaper and have given many more profile options than just buying one from someone like Cat Cams.
My usual cam grinders charge by the lobe, and while a 24V whiteblock would have been close to three times the price of reprofiling a redblock cam for example, it would still have been a fraction of the cost of buying new cams.
It would be interesting to see a normal whiteblock and T5/T6 can side by side for a direct dimensional comparison of their bearing surfaces..... and to see how much 'meat' is really in the T6 lobes.
I would have loved to have built a high-output N/A version of one of these engines if only it were more practical.