Somewhere around 5-5.5 EPA if you're sitting on a giant stack of Nightmare requests for you to no-life through.

It's about 8 aid requests per 7 DRs so... guestimating off of Arbor's High places favor grinding... you would need to amass somewhere around 250-300 DRs to match Arbor's Tribute bombs... Thus you would need around 280 Nightmare Aids for you to no-life through if you just did the low end of ~250 DRs, which requires almost 2 whole days of no-lifing your Nightmares back down to 0 from the unholy hell that is +1750 CP of Nightmares or LEVEL 59 in Nightmares. Oh and because of the maximum amount of actions per day and because you'd need to sleep, it's more like 3 to 4 days. Just do it during Christmas and make like 10-20 alt aid slaves spam you the Nightmare Christmas Card because that is -8 CP Nightmares, do it around the TtHlr for the alts card stacks to refresh and you'd probably be able to reduce the no-lifing to a day.

Congratulations, you are now in violation of the 13th Ammendment given how hard you owned these freshly-imported aid slaves from America, it's a good thing you're bri'ish.