I have a side-mounted P-Rail that handles either a scope or a RDS for my 181. It will work on pretty much ALL Minis. As RIBob mentioned, it isn't ideal and was first introduced for those of us with early Minis that had no provision for a scope or RDS (e.g. no scope scallops). But there are some unique advantages of it over other solutions - the main one being, with mounted, one still has an UN-obsrtucted view through the irons by simply changing from a chin to a cheek weld.
With a judicious use of Blue Loctite, it will do well and serve well. It DOES raise the eye-level for a scope or RDS, but it is mostly the difference between a chin versus cheek weld. One can certainly add cheek-risers without a problem if using a scope will always be the preferred sighting means. For me, I prefer just the adjustment between cheek and chin weld. To me, it is a carbine - not a sniper rifle, and using irons is a primary concern - what most other solutions don't allow.
A side-mount is easily reversible and in no way permanent - one of my primary concerns for the first firearm I ever owned. Returning it to "original" entails using a flat-tip screwdriver...
An UltiMak or Amega doesn't allow for a mounted scope/RDS to be co-existent with irons: to use irons, the scope/RDS must be removed. With the side-mounted rails, that is not necessary. I have an UltiMak with an RDS for my Mini-14 Tactical; that is enough.
To be sure, I have the side-mounted rail on my 181, but it seldom has anything mounted on it anymore: I have newer Minis to handle scopes and and RDS (1), and a bolt-gun to handle "sniper-like" 3X9-40 scope needs. Using irons for my 181 are "default" in its present configuration and I could easily restore my 181 to the original configuration without the side-mounted rail, but feel no need to do that other than for aesthetics. I like the quick potential to add an RDS or scope quickly if needed.
IT IS A CARBINE. They all are (except for perhaps the Target model).
All of this is unique to an individual's needs: intended use/needs and portability desires. For my farm, for a semi-long-distance shot on a known rabid fox or 'yote at 200 yards, my preferred will be my .223 Savage bolt gun with a 3X9-40 scope. I don't hunt and love God's creations, so this would be an extreme use. Groundhogs are welcome as long they keep their homes in the tree lines (which they do).
Don't know about 2-legged trespassers. We've had some with no serious confrontations (some were poachers and I don't think they'll return). Living on a remote property, one can't help but think of the movie "In Cold Blood". Sheriff's response here is likely just less than 30 minutes, depending on where they are at the time. "When seconds matter..."
Neighbors are of a similar bent...We'll take care of each other until the Sheriff's deputies arrive, given the chance. Otherwise, we can guide in the mortuary guys to pick up body bags if necessary (hopefully never).
Back to the original post, though, using scope scallpos or Ruger-supplied P-rails are the likely-preferred solution to scoping a Mini-14 if the model is adaptable. But don't discount the side-mounted rails if you want to alternate between irons and optics. Good and bad aspects, but they give a flexible option without needing an Allen-wrench or a screwdriver.
Just a perspective - not a recommendation for-or-against.