I'm 57 and am probably the worst climber on the forums that's not obese or has a disability. Other riders on the board can back that up. I'm in the OP's wheelhouse. I ride road triples. Usually a 52/40-42/30 in front with an 11-28 or 30 in the back. I may go a month or two at times between visits onto the granny. I have one climbing ride a year that I swap the 40-42/30 rings for a 36/28 combo. Anyway, my thoughts:
If you go with even lower gearing, you might be able to pedal faster, but you won't be getting up the hill any faster. You'll be spinning up that hill at 80 rpms............and only going around 4-5mph. That's what I do. You can either spin a really low gear and go slow or try to mash a bigger one and go a little faster. Take your pick.
On the top end, if you can't spin/hold a 50/11 at a decent clip on level ground, a bigger gear isn't going to help you much. Keep the 50/11 and try to use all of the gears. Tuck in on the downhills and conserve your energy. Work on increasing your cadence/power. Improvement will come.