Buckeye amps use only XLR inputs.
I went with Blue Jeans Cable. Belden 1505F, Neutrik XLR (same socket used on BA), Canare RCA (both connectors are standard and very nice quality), and optional color bands. They work very well.
I looked at worlds best cable on Amazon, but they didn’t have the lengths I needed. I’ve had enough quality issues with monoprice on other products and had read about some specific concerns that others had with their XLR / rca cables, so I didn’t buy there. Ultimately, I got a very high quality set of cables from a high quality US-based manufacturer.