Alas I don't have a Classic 5 Chris, I have my home built fretless Blingray which has a 3 band MM pre from a SR5 and a Duncan SMB4a pickup
I know what you mean about the tone, but it's nice on a fretless
I got one of Tommo's 2 band Sabre pre's to go into a build and out of curiosity wired it up to the Blingray
It definitely sounded crisper, very impressive, so I'm shoving another one into a 5 string build with a Delano MM pickup on the sweet spot for a homemade Classic 5-ish !
There are some Classic 5 clips on YouTube, worth a look, I think they sound lush but I'm biased!
Good luck with your dilemma, and yes, we've all been there!
Harry