Yes the leather is extremely thin and buttery soft but perfect for what I make. I agree with you that the qualities of the leather I love are also its problems. I am looking at trying a needleplate that has a hole only like the vintage singers. It still leaves the feed dog problem but maybe I could remove them and tape over the holes. Worth a try!
I use standard Gutermann polyester thread and have tried all styles of machine needles, including leather usually size 80 or 90. I did previously use a heavy twisted silk thread from Germany which was excellent but is not produced anymore
My list of several domestic machines include vintage (1980's) Pfaff and Husqvarna's, Singer featherweights, 201 and 99k, a new Brother embroidery/sewing and currently a Bernina 1260 which sews well apart from the sticky drag of the leather. I did mount a industrial wheel presser foot to the Singers which worked ok and was able to sew but still have the issue of the unsupported edge of the seam flapping around a little and the motors were a bit weak. I have thought about adding a servo motor to the Singer but that might be tricky to mount and sew slow enough.
Ideally, I would love to try a wheel feed antique Singer but they are very hard to come by here , or even the machine in the video above...
I have amassed quite a collection of domestic machines over the years in my search