@paulmwhiting, I do have Elements (version 11); thanks for the reminder that it can handle PS curves even though it can’t make them. I haven’t made much of an effort to try using GG22-to-QTR using the procedure you described, mostly out of stubbornness! I’m really trying to avoid the extra step.
Since making my earlier posts I have made some progress on improving my Lightroom-only workflow. First off, if you read the whole thread, I think @brian_downunda is absolutely correct regarding what you can and cannot do with Lightroom. As he explains in earlier postings, there’s no "preserve numbers" option in Lightroom, like there is in PhotoShop. The best you can do during export is get close. I confirmed this for myself at the pixel level. If you absolutely must have a perfect, 1:1 correspondence between the value of pixels on screen and the tone on the print, then you simply must use Photoshop. Using the procedure described below, the difference between what I saw on screen and what I see in print ceased to be important, or even apparent, to me. You’ll have to decide for yourself.
In the end I did come back to a softproofing approach (as brian_downunda recommended…). One of the things that held me back previously was that I use warm and neutral curves to get the tone I’m looking for with QTR’s sliders. In Lightroom, you can only softproof (and export) with one ICC – so which one do you use if you’re using two curves in QTR? My simple solution is to make an ICC from a print made using whatever combination of curves I most often use on that paper. For example, I’m currently printing a series of images on Premier Art Smooth Bright White 200 gsm, and most of them are 100% Neutral for the highlights, and then 50/50 for the midtones and shadows. Softproofing with this ICC in Lightroom actually gives me a good sense for what the print will look like (so I cheerfully take back my earlier suggestion that it wasn’t telling me much!) I then export from Lightroom using that ICC. It’s not absolutely 1:1 perfect in the shadows, but it’s awfully close. Of course for special situations, where you’re using dramatically different ratios with your curves, you can make a specific ICC.
Importantly, in a very early posting in the thread I said I was using QTR’s “Ink Limit (Shadows)” tool to bring up the shadows. I’m not doing that anymore. I find that it’s too hit and miss, and it’s not necessary if you can get control over the other aspects of the process (monitor calibration, QTR curve and ICC generation, image processing, etc.)