help with some info on my duster

The 4spd swap would be easier to do over the auto 727 which would bolt in and up without driveshaft issues. The lockdown linkage could be a pain to obtain.

I'd recommend 15 inch wheels. Know the bolt pattern size before you order them.
As far as "What wheel or style" goes, that is up to you. Go to the wheel and tire forum here to find out what other people have been able to fit on there Duster. Most posts have wheel sizes that included back spacing and there issues with wide wheels and what they did to get around a wheel and tire package that is normally to large for a stock wheel well.

What year Duster is it?