Sooooo..... I was one of those who had the XL Cart with a folding chair, cooler, and an umbrella strapped to it. I had the GPS tactical tall range backpack, and I carried enough crap to build 3 pistols and probably fix your car.
As I started flying to compete I took on a different approach. I picked up a sling backpack with a single compartment, and a camelback bladder. Added a couple 4x6 inch molly zipper pouches, a dump bag, and an ifak to the exterior molly webbing.
I can hold 500+ rounds in cases, 10 magazines, my pistol, fix it sticks/tools, chalk, gloves, a walkstool, shot timer, 5 foot collapsible tripod, GoPro, swabs/cotton dowels, mag brush, knife, tape, eye/ear pro, stapler, tape measure, and my belt on a carabiner.
Everything fits inside the bag in organized soft cases except the Stool, tripod, and belt. The whole setup fits in a pelican 1560 Case that has wheels and a telescoping handle. With everything in the pelican case it came out to 47lbs (the pelican is probably 5lbs).
The whole kit including pelican, bags, cases, chair, tools, ifak, and carabiner (not including pistol/ammo/mags/ear/eye/GoPro/belt) came out to about $650 bucks.
I took the same setup with me to 3 states for multiple matches on airline flights and it met all weight, size, and security requirements.
After running this setup, IMHO.... If you can't carry it, you don't need it.