I have the widest width stock wheels that were put on a beetle (at least in North America). 5.5J x 15, ET26. I run 195/65R15 Conti's. Max tire width at the ground is 61.25" not including any tire side wall bulge. There is a slight negative camber (stock) so the tires have maybe .5" clearance at the inner fender upper edge. Never had a clearance issue. Approx. 60.6" outer fender side to side at the top.
With a rolled inner fender edge and slightly more negative camber you may be able to clear. FYI.