Done with Snapshot testing on the Sylvan Caban +1/2 (AF3 RNG body). Thanks a ton Kirschy for the tips on testing methods.
Activating Velocity Shot with the body equipped then unequipping does not grant the boost. In fact, body doesn't have to necessarily be equipped while activating V.shot, just while firing the shots.
Both +1 and +2 offer the same reduction in delay with Velocity shot active (-10% or +5 Snapshot, similar to the Mirke augment).
On that note, Wiki's info on Velocity shot is incorrect, it's not -15% delay reduction, it's -10%. The numbers match on Mirke and V.shot.
I'd post my gathered data, but it's all jumbled up in an illegible Excel file atm, which is why I don't have any info on the R.att boost of the V.shot enhancement (if any). I'll try to organise it later and post any extra findings.
I did notice an increased amount of Rapid shots with the body equipped, though while samples are enough for Snapshot testing, they're not nearly enough to cover a low error margin Rapid shot test. I might get around to that sometime later.
Additionally, as a follow up to the above testing, I figured I'd take the time and test the Snapshot effect on some pieces which don't have any info on Wiki.
Basically got similar numbers on Zha'Go's Barbut, Sylvan Gapette +1, and Impulse Belt. All three gave a -3% reduction to delay.
I'll test Gapette +2 once I get around to completing it to see if it offers any more than 3% reduction.
Any suggestions on what else to test are welcome, or tips/methods for testing the R.att boost from the body.