When unable I always Amazon it. Sometimes it's also better than driving all over the place. I just toss it on the list for my next order.
We've only messed around with leathercraft for knife sheaths and belts. Sometimes I'd use 3-4 oz for certain things when making costumes for cosplay. I had a decent sewing machine and with leather needles it just powered on. Gave it to Mom for quilting because it would sew through 6 layers of denim without issue. All the ladies at the quiting group were jealous. It was just a mid level Brother from the early 2000s.
we have a pretty heavy duty simple Brother machine that can likely do leather work too so i may eventually use it for that sometime. i need to fix a belt and was wondering if i could put dental floss in the machine if it would work or not but i don't think the bobbins are set up for that... need to get some thicker thread for sure instead. no rush.
Leather needles are wider near the point similar to a triangle shape and the triangle edges are sharp to cut the leather as you push the needle through the leather. Some needles are straight other curved, I hardly ever used straight needles. Also I've never used a leather needle on in a sewing machine, always by hand. You can sharpen leather needles with a small fine file, just a couple of strokes is all it takes to get them ready for use I sharpened brand new needles before first use because they worked better when sharp. I used to use fishing line where the stitches wouldn't show for strength and longevity. Or the proper weight and colored thread were the stitches would be visible. Again touchup and repair. Had to make everything match as close as possible to what was being repaired. Almost always it was attention to detail that made a satisfied customer.I just used button/upholstery thread for the heaviest leathers, but regular thread worked fine for the lighter clothing leather. You must get leather needles, though. They cut through the leather so they don't break. Go somewhat slow and use wide stitch distance.