If you cannot find 15x6jj for 185/55/15 tires, then get 15x6.5jj or 7jj then fit with 205/50/15 tires, that's the best conversion size, not 175/50/15. Just make sure you use the proper offset and test fit into the car first before paying so can see if still can clear or may rub.

picanto confirm cannot use 205/50/15.sure rub..if u see most of the picanto setting on 15inch wheel they use 175/50/15

Ah IC, coz he said there's stock version overseas that came with 185/55/15 so the 205/50/15 is the closest conversion size diameter wise, plus it matches wider rims too. If 175/50/15 then it's way much smaller diameter. Or maybe at least use 195/50/15 since he said there's also another version using even 195/45/16, so by right 195/50/15 should still be able to clear if worry about 205/50/15.
Well not as common but not too rare either.

et40 above for 6.5j is quite rare.usually only can get stock rims with those specs.
advanti also recently produce this 6.5 et40 specially for bezza/axia.but only 2-3 design available if not mistaken