Glad you find the script helpful :)
I also had a short talk with Rawalanche a couple of minutes ago and he mentioned that you were having some glossiness issues. Yes, the Glossiness conversion is currently flawed. It was made back when Vray had it's default Phong and Corona it's ashikhmin-shirley brdf. Now things have changed with Vray and Corona using different GGX curves (with Corona clamped at the lower end). I intended to wait until Ondra had implemented an updated curve but it seems that this could take a while. Testing out what maps to what (2 times, for vray phong -> corona ggx, and vray ggx -> corona ggx) will require a bit of work and I currently cannot say when I'll be able to get to it.
I hear that you want to hold off on changing things until a new corona release, but in the meantime if we try to edit the script ourselves could you give us any pointers?
Modifying the glossiness value itself is kinda simple, but it won't correct any textures (that is a whole different story and a lot more complicated to do (that's also a reason why I don't want to do it twice :D ) ). But if you want to you can take the latest script version ( v1.18 ) and modify
line 1031:
r.reflectGlossiness = (if owner.converterSettings.vrayConvertGlossyValues then(1.0 - sqrt(1.0 - origMtl.reflection_glossiness)) else(origMtl.reflection_glossiness) )
The important part is this:
1.0 - sqrt(1.0 - origMtl.reflection_glossiness)
If you come up with a good temporary conversion, let me know and I'll see what I can do for the glossiness maps :)