Hi guys! Very sorry for taking so long to reply back to my own thread. I really appreciate everyone's feedback and intended to reply earlier, but now a few months later I'm in a better position to reply so here I am.
I could never get The Grandeur sounding very good on most of my pieces, but despite liking the free Piano One it still sounded a bit cheap. In the end I saw the Session Keys bundle on special and bought that. Of those, Session Keys Grand S was the one that stood out. I'm using that on most of my tracks now. One track still works best with The Grandeur, but overall Session Keys sounds much better to me.
Here are the two tracks I posted originally using Session Keys (plus a few other tweaks).
@john the free Piano One is apparently a sampled Yamaha Grand C7, though I agree it sounds more like an upright. Something lost in the translation to such a small VST maybe. But maybe for these fast pieces it's good to lose something? Too many rich harmonics on every note may be part of the problem?
@starise yeah I tried all the pianos in Komplete when I got it, but The Grandeur was the one that stood out. Was really interested in The Giant, but disappointed it didn't really sound that impressive in the end. Listen to just the first few notes of The Remaining Rag played with The Grandeur, and I don't think any amount of tweaking would fix it. There's some sort of popping or something on the attach of each note that I just found really annoying, whereas Piano One sounded so smooth. In some ways I still prefer those first few notes on the old free piano, but with Session Keys I think it now sounds best overall. I've also automated some different reverb effects in and out a bit to add life, and one reverb is there throughout which makes it sound like an older wonkier piano, which works for that piece.
@Leon T yeah I know everyone raves about The Grandeur, and yet for some of my pieces it sounded terrible. In the first track I embedded in the original post, that was using the free Piano One for treble, and the free Salamander, which you mentioned, in the bass. I found Salamander wasn't good up top, and Piano One wasn't good in the bass range. For a while I played with Piano One for treble and The Grandeur for bass, which was a bit better, but still not that great.
Thanks again for the advice, but for the most part, I just wasn't happy with the best piano which came with Komplete, and am happy to have found a new one that is working well.