for the moment, i can only post some screenshots with sysspeed and bustest with my Mk3 at 75 (74,3 Mhz wichamiga say) , set to 60ns for ram in firmware.
[ATTACH]5778[/ATTACH]
[ATTACH]5779[/ATTACH]
i don't have screenshots with Mk2. and as it run at 100 Mhz too, it won't be useful...
but finding somone else with a OC'ed Mk2 running 1/1 bus to compare is doable i think... HammerD can you help ? 
Well I have mine at 60Mhz now 1:1....I tried 66Mhz 1:1 but it's not entirely stable with my system (which has a Sonnet PPC in it) at 66Mhz....maybe it's the Mediator acting up at 66MHz, or my RAM. I don't know, but 60MHz is ok. I can post SysSpeed results...
BTW I have the latest mask 060 from Stan in Poland. And my board is a MK-II 040 upgraded to 060....