Those aren’t heavy pigs, those are known good models of saws that could possibly last you forever. I think you need another 50cc saw. A really sweet one. I don’t know anything about that 111, but you have the wrong bar and chain setup on that puppy regardless. It will feel so much nicer, so much more potent with a short bar on it. And a smaller chain. It will be much smoother in those small limbs. Like night and day.
Maybe sell one of your bigger saws and get a nice used 50cc for a couple of hundred bucks. If the 372 is nice, don’t sell that.
A decent 40cc saw will rip through those little limbs you’re cutting as fast as anything.
There are a LOT of saws from the late 80’s on that will run with all but the hottest current stuff. Parts can be a problem, but good saws really don’t go through that many parts for a casual user. Like none, basically.
Did I happen to mention your “heavy pigs” are some really nice saws?