While I have used tape on a number of cymbals over the years, you can often end up with a very artificial end result, and something that no longer has the key characteristics you need.
If you haven't already, try a thin, broad cymbal felt underneath the bell (just like the kind that goes under the bottom hi hat on most stands). I find that this dries out cymbal wash sufficiently, while still allowing the main characteristics to stay balanced. The 20" Dream is really a crash/ride (I think), and so you'll be battling the wash as soon as the volume increases at all.
See how you go.
Also, if you're thinking of buying a new cymbal, do you have a budget in mind? If price is no object, then I'd suggest a 22" Agop 30th Anniversary ride. Very different sound to the two models that you mentioned in your original post, but such a fantastic cymbal for jazz and associated genre at just about any volume you could need, right down to a whisper.