Yes I have tried both ways locking it place works best. If your type S die has that much play that you have to let the bushing float, I'd send it back. I have almost 0 run out on my cases after full length sizing. Real simple check your runnout with bushing tight and bushing loose. One thing I will add is that it is best to let your shell holder float with a rubber o'ring holding instead of that steel spring ring that comes with the press. And use only Redding die wax.
I will add that, "back-in-the-day" allowing the bushings to 'float' was THE correct method, however, as pointed out by LCazador here, you may well find that capturing the bushing delivers comparatively less
loaded-round run-out.
Several years ago, 'Humble Henry' Rivers advised me to try this method (I was a skeptic, who had NEVER measured loaded-round eccentricity). Humble had been struggling with a new die set and we discussed possible run-out solutions at length - so often that I purchased a tool to measure the fired-case:loaded-round concentricity. The best stuff I had was/is re-sized via FL dies featuring specifically dimension-ed lapped necks - dead-nutz . . . and almost all of my dies produced very good concentricity - however, none were a good as the lapped FL dies.
Following thorough testing and confirming, here's what 'Humble' suggested/insisted I try":
"1) with no bushing installed, adjust the Redding Type 'S' FL/Nk die for the desired shoulder set-back ('bump').
2) run another case into the die, drop the desired bushing (always gauge-pin your bushing - occasionally the stamped diameter is correct) into the die, screw the stem down, pressing the bushing
onto the case-neck until snug against the top-face of the bushing (this may require the judicious use of pliers!

) . The bushing is captive, and is dead-centered. You'll have zero - less than 0.0005" of run-out."
Damned if he wasn't correct!

I was surprised at how much run-out ammo loaded with most of the NK bushing dies exhibited! As noted above, in
red. The BIG issue: can we shoot (dope) the difference? Probably not, but concentric never hurts.
I have a pair of JLC converted dies which require no such set-up they work perfectly.

The issue with those: assuring that the bushing ARE what you want/need the to be; often, the bushing diameters are +/- 0.001" different than the marking. RG
P.S. This presumes a round chamber with concentric neck/shoulder/body.