I'm a Tyll fan but Comply is not anywhere close to neutral. My observations on Comply sound are pretty universal. Unless you are jamming Comply tips way the heck up into your ears like a triple flange, insertion depth will cause negligible difference in sound with them if you have a proper seal. The round ones are not much shorter than the Isolation tips. I've tried isolation series and the TSX type with and without filters. The foam changes the sound, the wax guard, not really.
Totally agree that all tips have an effect on sound, I just don't like the Comply house sound with most pairings.
I'm curious about Symbio foam only tips, but haven't tried them yet.