Just a quick note on the issue of "balance" as mentioned above. No offense meant to anyone; this is my finding.
"Balance" is often used a summative quality for handling. I can't find such a number any more than I can find a summative number for stock dimensions. Handling has the properties of weight, teeter-totter balance, unmounted swing effort and mounted swing effort. There is no single combination of these numbers that makes a gun's handling suitable for all shooters any more than there is one set of stock dimensions that suits all. Also, note that any brand, design, etc. can be built within a wide range of handling properties. I find SLE, SLNE, BLE, BLNE, and other types with identical handling.
American gun writers of the last century built a mystique around the SLE best work gun. Well, I love 'em, but boxlocks can handle identically.If, however, you are in love with the handling of the Brit game gun pattern, you will find a somewhat higher per centage of SLE's built to that pattern.
DDA