I was thinking of getting a combination "Ring cap mount for Anti Cant and Angle Cosine Indicator". But then started to think of the other ways that a bubble level could be mounted. A ring cap bubble is fixed, so the scope has to be rotated to align with the with the bubble. With a seperate rail mounted bubble the scope must also be rotated. With a scope mounted bubble, the scope can be leveled to the action rails then fixed inplace. The bubble can then be rotated on the scope tube to be in true alignment with the scope's vertical axis. Each method seems to have its pro's and con's. Which do you think is the best and why?