Yes, uk vti mounts will fit
Yes the inserts do make a little difference, although they make the same difference as an engine torque damper makes to worn mounts, they merely mask the fact that the mounts are worn
If your mounts are worn fit new ones, simple as, anything less is only a comprimise
As mentioned, Hardrace are a good upgrade, not much stiffer than oem mounts although they are MUCH cheaper than a full set from Honda, also the cambelt side upper mount is solid rubber rather than liquid filled so you're removing a weak point in the oem design