That is a super looking barrel and a great project you have undertaken for the Luger community! (If I ever get out from under a bunch of other projects, not likely
, I would love to tackle a target Luger with one of those barrels.
To get off topic a bit, with regard to the sights and trigger, there are some neat old articles in gun magazines from the 60s and 70s. "Skeeter" Skelton wrote and article "For love of a long-barreled Luger" or something like that that featured a specially made MMC sight adapted to the Luger toggle that appeared to be a viable option. I have a couple of MMC sights that I got from Hugh Clark that might be modified to fit (the adjustment screws are too wide to fit between the receiver rails).
I have posted an article from May 1974 "Shooting Times" a couple of times in the past that shows how to tune a Luger trigger and add set screws for trigger pull and over-travel adjustment.
The Luger is has potential for a really fine target pistol, and I hope your project encourages Luger aficionados to "go for it"!
Ron