I tried both of it when I built the original mRhodes Sampler Instrument:
– The release triggers I recorded were so quiet that I could hardly see any wave form. So I left them out.
– The difference between the “medium-loud” and the “loud” recordings was a bit unsteady and blurry – cause that’s how my Rhodes simply is. 🙂 So I made one velocity layer as a combination of these two recordings that is to some degree consistent.