For some of the lobe contour, roller diameter is very important, but of course not at all for max lift and base circle.
If the roller diameter changes, the effects are not continuous or linear.
Harley-Davidson, running out of money 50 years ago, used Chet Herbert V8 roller lobe profiles in their Sportster-based race engine. Dick O'Brien (the boss) said "I know there are weird vibrations and loss of control, but it's all we could do for this season".
Reason: Herbert SBC .750" roller, H-D .855" roller.