Hi Bill, I use the tumble lube (Lee Liquid Alox, LLA) on 1500+ cast bullets per month. It works good when conditions are good. You need bullets that fit the cylinder throats or bore of an auto properly or larger, you need relatively low pressures and you need to keep the loads reasonable.
For instanceI shoot in 45 ACP: 200 grain SWC (non-tumble lube type, H&G68 style) tumbled in LLA until they show "color" from the lube, they look bronze when they are lubed well, over 3.8 grains of Clays with WLP primers in mixed brass. Leading is non-existant.
In 38 Special I shoot 140 SWC, 140 WC and 158 SWC-GC without the gascheck. I tumble lube them all in LLA and shoot them all with 3.1 grains of Clays and up. Leading doesn't happen.
I have had leading trouble with poorly fitted bullets and with hot loads. The LLA won't take a lot of velocity or pressure so stay mild on both and you can shoot thousands of rounds between cleanings easily.