I found this video SUPER helpful... (Destiny)

by Doooskey, Kansas City, MO, Thursday, June 25, 2015, 17:57 (3260 days ago) @ bluerunner
edited by Doooskey, Thursday, June 25, 2015, 18:04

This video

Also, here is a link to a database with all values of Aim Assist for every weapon in the game.

Edit: Also, from the look of it, the highest aim assist in the game for a Hand Cannon is 90, and Red Hand IX sits at 89... So with Hidden Hand, it is probably as high of an aim assist as is possible in Destiny for a HC.