The High Road - an unconventional retro challenge

OK, 4 better; 5 free units, e.g. +bNb8 +bBa7 +bBb6 +bBa5 +bRa6

  *passes out* 

I utterly failed to understand who I was messing with. Even after many long and torturous hours in the tank, over many many days, I was unable to successfully construct a position satisfying this harder challenge. I would've simply given up and decided it was impossible, had I not suddenly thought to "steal" your position with the 8 free units, rearrange a few pieces, and then capitalize on all the extra pieces available to make everything work by sheer brute force. Incredibly, it still took AGES, but finally I arrived at the position below.

Fact is, you're just better than me at this - no ifs, ands, or buts about it!  And since it's now clear that no amount of effort on my part can ever change that, I won't bother trying to improve the problem anymore.

The one thing I'll add is that I'd be more interested in seeing what you could do in terms of further tightening the restrictions, as opposed to making as big a mockery as possible out of the current ones by maximizing the number of free units.   For instance, can the exception I made for the kings be done away with?

You can't imagine how much I loved that exception! The king opposition is a really powerful tool here. My feeling is that it is still possible with different king positions but I wouldn't bet my life on it.

By the way, what you call "stealing", I look at as "learning". I learmed those tricks myself by studying the creations of others. About 30 years ago a friend of mine watched me doing retro-constructions in an Amsterdam chess pub. He was bitten by the virus and went on to become the best retrograde composer in Holland and of world class. I am sure he "stole" many of my techniques and I am so proud of that!

If I am allowed to assume that white plays bottom to top then Nh2 is a free unit. If not, then it must be where it is.

You've done it!!!   Amazing! The original intention was that implied coordinates were part of the intrinsic character of a board configuration, so that the h2 knight would indeed count as a free unit. Though naturally, if I'd ever been able to imagine a position so stunning could potentially exist, then of course the criteria would have been as tough as possible.

It surprises me that you seem to prefer maximizing free units over maximizing the conditions that can be met. I'd have thought a hardcore problemist such as yourself would consider any possibility of free units as an unacceptable "hole" in the regulations for a construction challenge like this. Even as an amateur, it seems to me that a version of the problem allowing for no free units would be incomparably superior to the current one.

Creating free units is a way of demonstrating how much space is left for turning on the thumbscrews. Had it been my own challenge in the first place I would have raised the bar accordingly but I think it is only decent to leave that opportunity to you as the puzzle owner.

A version with 2 free units (+ 5 different batteries) and indifferent board orientation. I think this is the max for these criteria.

Sorry, 3 free units and 6 batteries is the max  

Well, I no longer consider myself the puzzle owner, as I've already exhausted every ounce of my creative resources on this (and then some!), yet still cannot even come close to the feats you've achieved with your latest positions. And I suspect you're still just getting started... and maybe even still just warming up! Whatever is needed to continue the problem's development, I certainly don't have it.

So you'll have to decide whether to let the idea "die", or pick it up and run with it. I've no doubt it could eventually be turned into something of truly professional caliber, but only with the proper skills and motivation. One possible way to try stretching even your most powerfully efficient constructions to the limit would be to specify the exact location of one of the kings, or perhaps a more general region for each king.

I suppose a 3rd option, which may or may not be feasible, would be to bring me "into the loop" regarding the methods you're using to continually forge ahead with groundbreaking and increasingly effective ideas. Whatever approach you're using, it must involve a fundamentally higher plane of thinking when compared with my own "caveman" thought processes.