You know there is already an LRB guide, right? It's in the general section, and it's also a wax barrel spacer guide. It wouldn't hurt to have two though.
No I have not as the L96 already has a really good air seal. (Normal L96 buckings are great)Have you ever tried the heat shrink mod with your L96? Saw it on here and was thinking it would really improve the airseal if it could be done.