I fear the light alloy frame will still show some wear where the cylinder edge contacts the cast-in-place cylinder stop during forced spent cartridge ejection. My 296, with that Ti cylinder, shows some 'bright' alloy showing after 5.5yr and ~1.8-2.0k rounds. Some have pared it away with their first 'Hollywood' rap of the ejector - use care! I did remove the rounded UM's Combats I had on it and replaced the OEM boots when I got my Robert Mika's pocket holster for it - it fits many of my pockets now.
With the backstrap/hump covered/insulated with those 'Combats', the 296 still wasn't the most fun plinker I owned, but it did get shot a lot more. I still shoot a few cylinderfuls when I feel the need. It's diet is the GA Arms 200gr Speer #4427 .44 Special Gold Dot now, ever since a similar Al-cased Blazer burst in my 696 several years back. At $47/100, the G. A.'s round is cheaper - and leave s you with nice once shot Starline brass.
So, the best way to clean a Ti cylinder - is to have a CS or SS cylinder! That added mass helps on recoil - and is more forgiving to clean.
The 646 had to have the strength of the Ti cylinder, according to S&W, due to the .40 S&W pressure & clearance. Neat revolver - probably a collectible today.
Staijnz