I think you have the distance between the scope bracket and the pistol correct, as it's seen in several photos.
Can you describe what you used for the spacer And the accurate-looking flash hider? Both you and @scottjua have flash hiders that look very accurate. (pardon if you've explained it elsewhere)
I believe I used nylon standoffs as spacers, for the time being, until I machine a part from delrin that's the correct thickness, and add three holes to that.
The flash hider is one of about four I've machined from delrin on my puny little lathe. Each one is a little different. The flash hiders from Boba Debt's run are more than a little inaccurate, unfortunately. The proportions are off, as is the transition angle from cone to body. And I'm not sure, but the whole thing may be a bit too long. This isn't really David's fault, because we didn't do enough research and discussion about the shape of the flash hider amongst ourselves, before the prints were deemed good enough.
I sold off one of the others recently, when I made a second Hoth gun. Some parts on this one are from earlier runs. The bracket is a bit off, and is an old Blastech, I believe. I wish I had taken more time and worked on putting those curves in the old bracket, I was simply pressed for time. I machined the slightly thicker "Thorens Disc" on this one, from aluminum.
This blaster was sold recently. The two lower screws on the Thorens Disc go all the way through and are met with M3 nuts on the other side, at either side of the Pistons.
Here's a couple shots of the two blasters together, before they were both completely finished, and before I sold the less accurate one, which is in front in the following photos...
It had one of "ThinkJedi's"? early brass scopes, which I had to hollow out as best I could with my drill press. Added my own lenses to it, and it turned out really nice, in a couple ways a little nicer than this latest run, but I prefer the scopes from this newest run, and their options! So, thanks to all involved for that!
Anyway, long story short. Too late. I custom machine all my Hoth style flash hiders. I've had interest in making more, and I'll eventually do that, but not on a large scale.
I think I have two left. Not the ones pictured above (actually, the two I have left may very well be the ones pictured above. The bottom one being the most accurate, I think). I have one on my personal Hoth gun, and one much smaller one that may actually be the most accurate.