I cut the trace between R5 and C6, easy to do, and soldered a couple #24 wires to the edge of the chips. And then the other ends to a 1K potentiometer. I was looking in the junk for a 2K but the 1K, 1/8 inch mounting, is adequate for a variable gain and takes up minimal space. Instead of 3.3 gain, it now varies from 3.3 down to 1.65 which is where I leave it. Modest layout, but I like having the booster and seeing the green LED since I am familiar with the broken Legacy base with the greatly reduced output.
Be cautious tack soldering the pre-tinned wires on to the edges of the chips, because too much heat will cause the chips to slide off their pads.