Looking at the pictures it appears that some have added the weighted shims to the rear of the stock. Would like to hear your thoughts on if this helped with some of the recoil when changing to the Bravo stock. I see that they offer a set of three at a fair price.
I use them on all my W3s. I have three trim levels I use, and I use weights and spacers differently depending on what I'm doing:
(1) Super-Light. This is for matches like the Mammoth Sniper Challenge, Vortex Team Sniper Challenge, or matches that require a LOT of timed rucking. For these matches, pounds = pain, and I trim out my rifle as much as possible. I use a fixed-back W3 with polymer furniture, and everything is as light as can be. There are no weights anywhere. I sacrifice both recoil control (total weight) and balance to get it this light. This configuration also includes a change from a Vortex Gen II Razor to a Vortex Razor AMG, and my 6.5 Creedmoor can get under 14lbs with a bipod and magazine.
(2) Medium trims. For some matches I just add enough weight to get the balance where I want it. This usually includes a bit of weight to get the balance point a few inches in front of the barricade stop. But I rarely use this configuration.
(3) For heavy matches, like PRS / NRL matches or anywhere I'm not worried about carrying the rifle around, I start by adding all the weight I can, and tune with the LOP spacers at the end. Weight includes the fore-end ballast block, polymer furniture filled with lead shot and 2-part epoxy, heavy bag rider, and more. Then I add just enough LOP spacers to get the balance point back where I want it.
So in answer to your question, YES, the LOP spacers are very handy to add some weight to the rifle, but because they are so far from the balance point, they are very powerful, and the change the balance point a lot. In other places on the rifle, more is better. For the LOP spacers, have several on hand, and use them to tune the balance.
-Scott