I shot an original 75 last year, with a Bushnell 6-24x40 front AO scope. Won springer class at the club with the setup.
The long scope helps the scope Bell be forward of the loading port, so more space under the scope.
I have also used old tasco 32x, a tasco custom shop 10-40x, optimate 36x44 all of which were £150 or less.
The optimate was later badged as a weaver.
I still use the Bushnell on my TX200 springer.