You've raised a perennial issue & one which isn't made any simpler by the fact that there are so many ways of recording "stereo". A lot depends on what it is you want to record. Is it festival music, brass bands, street ambience, nature...? There isn't one single setup which is optimal for everything (like everything else in life!)
You say you're currently using NT5s with a stereo bar. Presumably you have experimented with the options which this offers you, viz: XY (coincident), ORTF 17cm angled out 110deg, NOS 30cm angled out 90deg, and misc. variations of these. In which case do you already have a preference, or is it just flexibility which you seek?
I think you'll find that many folks (myself included) prefer some spacing between mics as opposed to using a purely coincident X-Y pair, and bulky windshields such as the Rycote BBGs will work fine with all of these configurations. In fact, since you already have the Rode mics, this arrangement would allow you to try spaced omnis, too if you get the NT55-O caps for your NT5s. This is another valid configuration for recording "stereo". There are cheaper foam windshield options, Rycote "softies" come to mind, but these don't provide a sphere of still air around the mics as do the BBGs.
If you get the Rycote BBG "baby ball gags", you can use your existing Rode mounting bar together with any type of small shockmount which will fit. Rycote do make a rather nice stereo bar c/w with the new "lyre" suspension mounts. I've seen this advertised as part of a kit alongside a pair of BBGs and you might find that you can get a good price for the complete bundle.
As for a full sized basket windshield (Rycote / Rode), you won't be able to fit standard length SDCs (such as NT5s) inside in any kind of stereo configuration. It's possible to do this with smaller cards such as the Line Audio CM3s, or Sennheiser MKH8040 ($$$) (for which Rycote make a complete windshield kit), but then that's getting away from the immediate issue of doing what you want with what you've got, without shelling out too much cash!
I think the decision making process is something you have to slog through, and it does depend a lot on what you're trying to do. How much wind do you need to cope with? Are the mics on a boom or tripod? Do you need to trek miles with the thing over your shoulder? etc.
You've already overcome the first hurdle in realizing that wind protection is important. So good luck!