Nice squeezing to fit the battery in a 1590A. Are those Lumberg jacks? I like their placement. There is still room to work with though. For instance, you could save some room by relocating the 9v jack, use an "outie" rather than an "innie", mount circuit cards on the pots, consider a way to use the space above the IO jacks (such as a circuit card on standoffs holding short components), and stack two cards in the large cavity between the jacks, 3PDT, and battery. I think you could squeeze 3 pots with room for knobs, maybe a toggle too. You'd be surprised how much less room 26 AWG wire uses than 22 AWG.
FYI- I've completed a fair amount of distortions, Delay, Reverb, Phaser, Compressors, Envelope Filter, and Chorus builds in the 1590LB; and distortions, reverb, chorus, and compressor in the 1590A (Chasm Reverb, Little Angel NYE, and Engineer's Thumb). However, my builds are on perf, not PCB, so these may not be very interesting to you. I hadn't really considered using a battery in a 1590A, its just not something I use.