If you're having trouble focusing those rather fast lenses, what about getting a Nikon body with good AF, e.g. an F100, or at least a good electronic focus indicator. If you want, you could affix an external viewfinder to the body for ease of composition and then just let the AF do its thing
Yes, an RF will provide you a nice big viewfinder, but you'll still have to focus using the patches. I wouldn't assume that'll be any easier without trying first- some people find it difficult. (I happen to like RF focusing and not looking through the lens)
Most recently, I picked up a bessa T, which I bought just to use the 21mm color skopar. Terrific combination. The external VF is so much fun to use.