I think I'm decided on the spacing for the large caps now. I'll be avoiding Ø18 as those have been deemed a negligible change, and I believe this thread has picture confirmation of Ø16 caps fitting in the normal spacing. I'd still appreciate hearing anyone's thoughts on audio grade vs. high endurance type electrolytics in the coupling (C3, C6, C13, C14) vs decoupling (the rest) positions, if I've understood the circuit correctly, as well as output resistor choices (R8, R9) that people have tried. This is all very interesting, but still quite mysterious. It's still a pretty tight space on the board since I'd be working in the lineup of the RCA outs and a couple of the film caps and large electrolytics. I'm sure I could figure something out if I really wanted to use those Ø18 caps, but after messaging Pete and getting his feedback, I think I'll be working with Ø16 or less since the 1000uF up-size would have negligible effect on my headphones. I think I'll avoid any lead acrobatics for now, but thank-you for your input. I think the default board has multiple pot spacing options, at least enough for the one I will be using. These are interesting, but I'm sticking with the default board for this build. I'll look at custom boards or designing my own if I get deeper into this stuff.