origin bolt on rear flares are big enough to accomidate a 8.5j -22 with 195 (using standard T diff) so 8j -34 (adds 30mm from each side of the diff) is only 6mm more poke (each side) than my 8.5 -22 and the origins had a good 10mm left in them.
footnote:
-15x8-4 (effective -34 due to diff) should fit with origin rear bolt on flares, providing tyres arnt wider then 195/