Keep in mind that if you DO go with 2.5mm balanced, you would want to use a single cable, not a dual cable (because one side is SE). Hifiman made this more confusing than they needed to IMO.
You certainly can use a single SE cable with these. When you have a headphone that is wired to be balanced, you can always use a non-balanced cable with these as well as balanced. But you cannot go the other way round. So, you could look at it this way (looking at it from the source connector up to the headphones):
- TRS to TRS = OK
- TRS to TRRS = OK
- TRRS to TRRS = OK
- TRRS to TRS = BAD (shorting grounds together unless you have a specialty cable that rectifies this)
P.S. Honestly, I am not sure why they added the ability to have a dual cable on these, because if you use a single cable into the balanced side of the headphones, you can use either cable with them (SE or balanced). The OG Deva have only 1 port into the cups and it is balanced, making it easy to figure out what you want to use.