I checked my Fiat Speedlines - 6Jx15H2-40, so I guess the offset is 5mm greater than yours (so yours sit further in?). 185/55x15 tyres are standard.
If you have a true 98mm PCD then you should NOT need wobble bolts, maybe your bolts are just too short if the wheel section at the holes is thicker than on earlier wheels. I had this problem when I got a second set of Mk1 Brava alloys, my "Speedline" bolts were 6mm or so too short. Also the hex nut size changed from 19mm to 17mm between Mk1 and Mk2.
You are lucky that you can get thinks fixed so cheap, especially the wheel straightening! I guess the roads can be bad in your area, to cause the damage.
It should be good when finished.....