As ever Doug, that's a very comprehensive, thoughtful and knowledgable reply you've provided.
In response I'd make the following points.
1. Whilst I don't own an Arca RM3D/i, I have used one. No two ways about it, it's a great piece of precision engineering, and in terms of repeatably being able to set a very precise distance there is nothing that can presently compete. However, in practice, I found this level of precision - for my requirements - simply overkill. Infinity is where I live 99% of the time, and even an old belt-and-braces bellows camera can get me there. The precision of the Arca is nice to have (and talk about!), but not a practical necessity for me. IMO 'precision' has become a very useful tool in this digital world for each person to brow-beat the other one with: e.g. Each 'tick' on the Arca ring represent a change in the plane of focus of only 1cm? … leads to … 'Holy cow, how do you get by with such a sloppy focussing ring, I need at least 0.1cm precison'. And so forth, ad nauseum. Following the argument to its logical conclusion, landfill sites the world over will be full of Arcas, Cambos, Alpas, Horsemans etc. as none of them are clearly up to snuff when it comes to repeatably setting the lens to a distance of 145.343265m with a 0.000001 micron sensor. In practice however, this isn't the case, and great work continues to be produced with all these systems, and that will continue to be the case even when each 'tick' on the RM2001d/i represents 0.000001mm. As a sales and marketing tool, 'precision' has been a gift; no one is generally going to argue that a system should be less precise are they? And, as precision increases, the cost to the end user rarely goes in the opposite direction...
2. Adding a shim to a lens in order that infinty focus on a lens matches the little number on the accompanying Arca card isn't something that I (or anyone else in fact) should lose sleep over. Even the best CNC machining will only get you so close, and shims are the principal way to minutely adjust the position of the whole lens (though there is always a tad of latitude on the helical (if the lens uses one), and you can alter the infinity position on that if needs be). As I've said before - sell me the CNC'd and anodized mount, a pack of shims, and send me on my merry way. Sell me the helical as well if you want, but I can pick those up from Schneider/Rodenstock direct. If this isn't everyone's cup of tea, then let them send their lenses off and bill them accordingly. I want to see users offered the choice to do one or the other. Indeed, even if Arca did the work for me, I should still check how this works with my digital back. As Arca users have detailed elsewhere, this involves having to apply an offset to Arca's numbers if there is a discrepancy … so, that being the case, what exactly have they paid for (other than the hardware) that they couldn't themselves have provided? i.e. if Arca's location of infinity for this lens, isn't in fact infinity for this lens with my digital back, then all the measuring, calibrating and shimming they've undertaken in their factory has pretty much been for nil. So, if their infinity isn't my infinity, do I get a part refund?
3. As detailed previously, I think a really good reason to do this work 'in [my] house' (besides the speed and simplicity of doing it yourself) is to avoid the hassle of import/export. It would be nice to think the dealer I dealt with in order to get my lenses retrofiited was some cowboy operating out the back of a truck - they weren't. I am still interested to know what temporary import facilities are available for Arca, Alpa and Cambo - since you deal with the former and the latter, perhaps you could tell us? Unless things have changed, I know from experience that at least one of the big three does not have the facility to temporarily import, and are happy to instruct their customers to, basically, break the law. Now, no one is saying that this is tantamount to robbing Fort Knox, but it's a situation that could so easily be avoided if the hardware was available separately; there's really no need for these companies to treat their clients as ham-fisted, drooling neanderthals who don't know the difference between one end of the viewfinder and the other.