I can try it with equal proximity. My reasoning for doing that was because I wanted to compare the best I could get out of each specific Mic
That's fine as far as it goes but proximity effect is very hard to control for especially when you're standing and singing into a mic. If you want consistent results across mic tests, I suggest to choose a standardised distance from the mics which is outside the proximity effect zone by a small but safe margin, using the pop screen as the barrier, as guitar legend quite rightly suggested.
Otherwise it's almost impossible to judge what is the natural sound of the mic and how much is the bass boost of proximity effect.
Again, I suggest mixing a fully produced backing track with an
unproduced vocal track is unhelpful.
Regardless of the mics tested, your voice would sound
much better in a finished mix, and it's the finished mix which everybody hears, not a mixture of finished and unfinished. You used the words, "clarity and sheen" as the improvement you were wanting. Clarity and sheen could well describe the improvement to the vocal line once it was produced to match the backing tracks, and "sit" properly in the mix.
Just on its own, basic compression would make a huge improvement by lifting up to audibility your quieter parts, (clarity) and taming the ragged, sharp spikes in volume (sheen). Just some thoughts.
I guess my overall point has been that enormous R and D has gone into the manufacture of mics for generations. We are the beneficiaries. Be thankful for that.
I fear you are "stuck" at the mic stage and need to get "unstuck".
Why not just buy a reputable mid priced vocal mic (edit: I forgot. You might already own some) and
get on with what you love: singing and recording? Once you commit to the equipment, you can start to make complete recordings and productions. That's when you start to learn all sorts of things -by doing it from start to finish.
Cheers Tim