Coonan mentions barrel flex in his pistols due to the higher pressure of the 357M. This may be for another reason for being generous with lubrication.
Actually, Dan Coonan and somewhat former/formerly regular poster Kurmudgeon on these forums (a former Coonan gun builder & tester) would clarify that it's the slide that does this flexing under full recoil and that is why it's been specifically
designed somewhat loose -- as the whole thing tightens up under this full flex. If the slide felt any "tighter" then it would be locking up or galling or destroying itself with each cycle when that slide flexes.
Dan Coonan does indeed recommend that his gun is run wet-- he says that if you shoot it and you end up with flung lube on your shooting hand & arm, that's the right amount.
Dan Coonan knows infinitely more about his guns (and most guns) than I'll ever know, but I can tell you that I do not
run mine that wet. I run it nicely lubed with nothing flinging anywhere, but the key for me is that I run it with strongly built handloads. From 125 to 158 grains jacketed and 158 grain to 180 cast lead, with a few different powders. Mine runs all of the time in my hands. It will fail to function in certain hands -- same guys each time, who don't manage to grip it the way the pistol wants. In my hands and most of the folks who shoot it (and love it), it runs like an animal and just begs for more.
as for the lube, I started with Shooter's Choice gun grease which I like on most of my semi-autos because it stays where I put it. When I found out the Coonan is recommended to use FP-10, I snagged a bottle of it and I've been using it on the Coonan. FP-10 is definitely a lube and not a grease, and it's not cheap stuff.