If the shutter can be removed a quick flush with Isopropyl alcohol is usually enough nto stop the sticking. It's a standard shutter so any repair shop can give it a CLA.

Standard cassettes should fit but like early Leicas you may need to retrim the leader.

Wirgin themselves weren't known for precision engineering but they were still quite a reasonable manufacturer, there was more hand craftsmanship to assemble their cameras particularly the later SLR' than other manufacturers.

Ian