I am the proud new owner of a IIIa. From the first batch, and alleged provenance includes being taken from a German tank officer (interesting and sad for him if true). I've shot a few test rolls after an "amateur CLA." This includes removing the shutter crate, ronsonol to all of the ancient grease, and some fresh OTIS (dry grease) applied to the greased mechanisms. I love the images. I'm using the Elmar 50/3.5 and 90/4. There's that vintage look that I was after. However, the fast speeds of 1/100 and above are about 1-2 stops slow. Reviewing the curtain gap with a backlight and iPhone shooting 240fps video, it seems like the gaps are large. 1/100 leaves a little more than half of the frame open. 1/200 about a quarter. 1/500 close to 1/8, and 1/1000 barely less. Given a curtain transit time of 1/20 (which I've read elsewhere on the forums), I'm assuming I should be about 1/2 at 1/60 and roughly decreasing by halves thereafter down to about 1/48 (just shy of a millimeter) at 1/1000. I know the sure fire bet is to send to YYE or another professional for a full CLA, but I haven't got 150 in the camera, and I'm comfortable shouldering some risk. My main question is if I should try: 1. disassembling further for more CLA (I.e., disassembly of the shutter crate) 2. Reattaching current curtains at a different point (they are in good shape and appear original at least in the sense that they are sewn and not quite fresh) 3. Further disassembly and curtain replacement. If I go 2 or 3, or even 1 and 2 or 3, I'm curious as to how I should vary current placement to close up the gap. I have the utmost respect for this camera, the right toolkit, and experience on quite a few other disassmblies/CLA. I don't expect perfect 1/1000, but I'd like to shoot asa100 f16 1/100 on a sunny day and have faster speeds than my Argus C3. Thanks in advance. P.S. Included is a collage of 12 images. It is 1/30-1/1000. 6 opening and 6 closing.