On the ragged edge of the world I'll roam,
And the home of the wolf shall be my home - Robert Service
I'm 5'7" 195#. Huge on my frame would be 215-220+. I do a ton of plyometrics to go along with the lifting days to build fast twitch muscles. I've always been more of a sprinter and short distance runner (1-3 miles). However, I find in USPSA, the ability to shift my weight and get out of position quickly and then stop/stabilize my momentum can be a huge advantage. And it's not usually motion in the forward direction in USPSA, which is really trained by sprinting/deadlifts/squats, it's more a sideways shuffling motion. Some of the agility work I do includes an agility ladder workout and some multi-directional short distance cone sprinting drills like a box drill, illinois agility drill, and a side to side shuffle run drill, often with a weighted vest.
How heavy is your weighted vest?
One thing that helped movement for me a lot before my health issues was doing body weight lateral lunges after doing deadlifts and squats or weighted normal lunges.
I eventually morphed that into what I called lunge star I would do body weight lunges laterally, as well as obliquely forward and rearward. For a total of 6 different directions/angles, avoided going straight forward because figured normal exercises hit that fine.
Thought about getting weighted vest because DB's didn't work for the lateral lunges for me.