First, I have to call foul on the rubber band thing. It accomplishes nothing. Adding pressure into the brake system with the rubber band will cause air bubbles to shrink - and be less likely to float up through the lines.
Bubbles will float to the highest point they can reach... but they won't float down. Some air gets trapped in the caliper cylinder, the switch tee, and anywhere a brake line doubles back downwards.
Normal bleeding by pumping fluid through using the master cylinder is better than nothing but can leave air in these traps because the short pulses of fluid flow allow bubbles to float back up after being moved down a bit.
Pressure or vacuum bleeding moves a relatively large volume of fluid down through the brake lines at relatively high velocity, hopefully flushing any air out. You need a pressure/vacuum bleeder, and it can use a lot of brake fluid.
Reverse bleeding is similar to pressure bleeding but it goes from caliper to m/c. This moves bubbles upwards, in the general direction they want to float anyway.
It's pretty easy. You pump the removed caliper piston most of the way out, then squeeze it back in fairly quickly and flush any bubbles back up the reservoir. There are cautions - brake fluid can really spray out of the reservoir... and it eats paint. The reservoir can overflow if you aren't careful with how much fluid you add.
In my experience the results are equal to pressure bleeding. You can do it yourself and avoid buying a pressure bleeder or paying to have it done.
The difference - for me - between the best "normal" bleeding I could do and reverse bleeding was night-and-day: very solid lever feel rather than mushy.
Your issue might not be from air in the system. You don't indicate what "grab well" means. If, squeezing as hard as you can, you can get the lever to the bar: something is wrong! If you can do a good maximum braking panic stop from speed without the lever hitting the bar, the brake is working passably. If your idea of "grab well" is not from a road test: do a road test. You can't guess braking strength otherwise.
