This is pretty weird. I think almost every reverse schema I've seen always prioritizes rebidding 5+ in a major, any strength, ahead of reverses. Helps avoid tempting opener to bid 3M with a strong 3451, when responder has 4 sp only and wants to get out in 3d.
There are some schemes that have 2M 5+, weak, and passable (less common), but still with weak and 5+ M they rebid 2M instead of 2nt first. Suggest 2nt = 4- spades instead of 4+ spades.
Unless rebid 3h later, in which case 5+ spades by inference.