Hello,
I had one and was able to sew with a 160 needle. The system for the needle is 134-35. The machine can handle medium weight leather. If you sew with the 160 needle you must take a smaller bobbin thread, otherwise it won't sew correct. I always used a straight point but better is to take a cutting pointer, either LR or S point. If you want to sew ticker leather like shoulder aso. I advise you to buy, If possibly, a somewhat heavyer machine. All in one I was quit happy with but was able to buy a Adler 269-373, which is able so sew a bit ticker leather.
Yours,
Bert