Softer tips on Treble register?

[Krubbadoo]

Hi.
I would like to hear a warmer tone on the top range. I've seen suggestions about using softer tips. I don't want to use felt tips but rather softer Neoprene or rubber tips. Any suggestions? I have a few spares Red, Green Yellow and White tips. Would these be useful instead of the standard woodcore tips?

Thanks!

Martin