Same as the Cougar 108's, and yes, the wheel choice is buggar all, ROH wheels will custom make some as long as your pockets are deep enough, I ended up getting mine from
www.bigotyres.com.au at Moorebank, they had some 19" blanks which they drilled out for me and they used a hard rubber spacer to take up the slack in the centre bore.
Cheers
Mark