You don't even need to remeld your gear to get a sense of the difference. Just look up any target dummy video from Heavensward. Here's an example:

Link

The first Blood Weapon use ends at around 0:27, so you can use that as comparison of the before/after. There's a reason that Grit felt so wrong in Heavensward/Stormblood. Even the animations just feel right with the speed boost on. This should be your baseline speed under Darkside, much like GL and Huton is for MNK and NIN, respectively.