Never too many questions! I use a 70/11 needles actually. There were just 2 studs above the pocket on this one...tho I do have a couple others that have more.. I noticed when I bought the jackets that there were several that were cut the same but had minor differences. I bet you probably have one like those. I have stitched over seams on other projects but would never recommend it on denim. It was tough enough to hoop over seams! If you stitch over thin seams you have to slow the machine way down as or the needle will probably break. If you embroider stretch denim the most important lesson I learned was to use a heavy cut-away stabilizer and be sure not to stretch the material in the hoop. Try a small 'open work' design on one area of your jacket and if it works for you then try a bigger design the back. Doing denim jackets is a lot of fun. I sometimes buy second hand jackets, wash and iron them then do embroidery on them. Then I give them away to kids or adults who need coats. I tell the people that they are my 'practice' projects (which is true) and then they do not feel so embarrassed about taking them. 'Go for it' with your jacket... I bet you will do great!