Me? I'd rather put a muzzle brake which will hold my recoil and flip down and make my shots more accurate to the volume of fire so I'll have fewer "incoming" to even worry about.
"Are L1-A1 rifles better than STG-58 rifles? Are Heckler & Koch G3 rifles heavier than STG-58 rifles?"
L1A1.....I' a wee bit confuzzled...is that the British "Bullpup" Battle rifle? I have some friends that used to be in the British army (and SAS). When they were soldiering for a living (seems everybody gets older and retires or moves on) they just hated that thing. I dunno why. I do think that the H & K series is a heavy rifle, but a durn good one....well proven in many conflicts.
"Anybody have any recommendations on a good home defense models of 20 gauge shotguns (he would prefer models which have a stock and not just a pistol grip)."
I wouldn't own any shotgun that didn't have some form of stock, even a folding stock and I dang sure wouldn't shoot such without the stock extended! It's just a personal preference, but I'll take a semi-auto over a pump anyday for self defense. I've seen the "short stroke and jam" scenario under competition conditions a lot of times, hate to think of what might happen when lives are on the line.
My Benelli M121 12 guage recoils about the same as a Remington 1100 20 because it's recoil action and "pro-porting" absorbs so much of the felt recoil. It's got an extended tube and rifle sights....Mighty quick. I can rattle off all rounds before the first hull has hit the ground and the hits will be on target at self defense ranges for such a weapon. VERY accurate with slugs, too!
I have an Australian inch pattern kit assembled on a metric receiver because at the time I also had an STG-58 metric rifle on a metric receiverand did not want another mag to buy.
Go over to the Marketplace forum at the FAL Files and see what people have for sale. A lot of the guys love to build their own but can't afford to buy a lot of guns so they build one, shoot it for a few months, sell it and build another.
I had a Springlfield M-1A that I bought in California. After relocating I had a flash hider put on. Barely any muzzle flash at night now with the flash hider on it. I was much more pleased.
I don't have experience with muzzle brakes, but I can tell you they sure are annoying when you are shooting along side someone else that has one. I guess this is one way to win matches, distract the other competitors.
I like the flash hiders. It gives you an extra split second with each shot to re-aquire or stay on the target. My Garand does not have one and the flash obscures the target for a split second.