Like you, really like LTWOO/campy style shifting. they are (as far as I can tell/tested) completely shimano compatible (10/11/12) and mix well with them. I have tried Ultegra RX with LTWOO and worked just great as LTWOO has limited cassette range compared with Ultegra RX.
So, an update on this now that I have been able to put around 200 miles of use on these through all the rain and cold weather here in PNW - the thumb button shifter is impossible to hit from the drops. I just can't reach it with thick winter gloves. It can only be accessed from the top of the hoods but I guess that's how it is supposed to be. These are installed on a very W I D E flared bars so they are at an extreme angle. The shifting took me some time to get used to. I am sure these will be better on regular road handlebar rather than crazy flared gravel bars.
Secondly the clamp band tightening screw is at wildly deep location on the shifter. Maddening that did they not think of having that screw more accessible. I had ball head hex key and with some jiggling I was able to get it into the screw head. Total pain to tighten, made worse by flared bars. If you are playing with the angle, trying out different positions, these are the absolute worst shifters to do so with.
Third. The downshift lever is wobbly. It is supposed to go in the brake lever's underside but it is not perfectly positioned to do so. End result, when you press the brake lever this little shift lever tries to "float" above the brake lever instead of going in the recess. Not a big issue but it shows the build/quality control is meh. I fear after some wear, that lever will pretty much refuse to stay in place.
Now for the good part - the shifts are crisp. As in I can't fault them against GRX 400 which were there earlier on the same bike. The indexing was easy peasy (Sunshine 10s 11-42) and I particularly like the cable routing. Its fiddly because you have to thread in the cable through a plastic part but once done its good to look at.
The derailleur is bit sloppy though. After installing it, there remains some play around the big mounting bolt. I almost thought I did not tighten it enough and double checked but no, that derailleur just has slop in it. Thankfully, once the cable tension kicks in the slop goes away and does not hamper shifts. In my short experience there hasn't been a missed shift.
And despite the downshift lever being loose, it works perfectly and has good resistance to it. I am going to keep an eye out for it though.
The cable routing at shifter end is fairly straight forward but I am not a big fan of rotating brake cable holder. Also I made a mistake and used regular brake cables with hydro-mechanical Onirii calipers. Now the brakes are all spongy and feel weak. I have compressionless housing coming in but too lazy to change things again because the bar tape job turned out phenomenal (for a change lol). Hopefully, the spongy feeling isn't because of the levers.
