Hi Kris,
First of all, sorry for answering you so late. I’m a Police Officer too, I’m not sure if you’re asking me about the installation or in relation with the tactical use of Mesa attachment.
In our Unit, we followed step by step the instructions that very kindly given me by ‘benelliwerkes’. Related to that particular, you must pay special attention at the moment of filing down the “two parts spare” in order to not reduce too much the diameter, but in case of this happens, you can use a special blue locktite for guns.
We prefer to file (file-check….., as many times as you need) the spare to prevent any kind of irreversible damage in the pistol grip (and also in the receiver of the shotgun cause of the drilling of the weapon), take special care with this.
As I mentioned before, following the instructions (and watching the photos) you won't have any kind of problem.
For the rest, our experience with mesa push button it’s being very positive, the only ‘negative’ aspect it’s been that some shooter’s informed of a little upset when he’s shooting due to the gun recoil, the swivel hits his thumb,….nothing dramatic using tactical gloves.
By other side, we use our shotguns in both configurations, with one or two points slings, that’s a personal preference of the operator. Personally, I prefer to use the one point sling (I've recently acquired Magpul MS3) because the gun falls down vertically and keeps its position in front the chest.
I hope this helps you Kris.
Regards Dom.