I would be very careful using speaker taps. It does work well for certain difficult headphones. Like the HifiMan Susvara and older HE6 models. They needs tons of power and so speaker taps are a good way of getting them there. For most other headphones of normal sensitivity I wouldn't recommend it though. I almost ruined a pair of expensive Focal Utopias that way!
Have you looked into the Pass Labs HPA1? It's a really great headphone amp.