[dataweaver]

Let's see: RPM imposes a -5 to the activation roll if you lack appropriate ritual elements, with a separate penalty for ritual space and for material components (the latter being based on the Sympathetic connection thing). A -5 penalty is less restrictive than not being able to use it at all, which is the default for Accessibility. I'll get back to that in a bit.

Power-Ups 8: Limitations gives the Accessibility values for ritual-like restrictions, and it doesn't match up with Pyramid #3/66: the latter counts gestures and chanting requirements together as -5%; the former counts each one on its own as -10%, for a combined -20%. The former also assigns -10% to needing material components; I'd use this value for the RPM Sympathetic connection requirement, but halved if its lack imposes a -5 penalty instead of outright forbidding it.

This is from memory; I don't have PU8 on hand as I write this. It's possible that its discussion of the Accessibility Limitation gives guidelines for only being able to use your power in specific places (such as ritually consecrated space), so I'd recommend reviewing it with this in mind. My gut instinct, though, would be to use a -10% value for Accessibility (Sacred Space), but halved if it imposes a -5 penalty instead of flat-out forbidding it.

(I'd use similar logic with respect to the Preparation Required Limitation to represent the Time element in RPM: if you can forgo the “required” preparation by taking on a -5 penalty, halve the Limitation's value.)

As for Ritual Adept: if you want the effects of Ritual Adept on Rituals-as-Powers (i.e., not having to worry about Ritual Space or Material Components), buy off the associated Accessibility Limitations from the Abilities that aren't hindered by them (or don't impose them in the first place) instead of taking a separate Advantage.

That is, Ritual Adept shouldn't apply to Powers: if you want its “benefits”, modify the powers' costs directly.