I don't think I'll be putting a £400+ air chuck on my £30 track pump
Who's talking about £400? Even the Hirame is under £100 including delivery, the knock-offs and KCNC are more like £30. I've got a Hirame, and it was indeed more expensive than the rest of my SKS Rennkompressor but it changed it from a £50 paperweight into a useful tool as far as disc and H3 inflation duties are concerned.
The Hed is much less of a problem than some discs anyway. The SKS EVA or similar heads should work in the big valve pocket on a H3, but multi-valve heads with the Schrader hole in front of the Presta hole probably wont.
Who's talking about £400? Even the Hirame is under £100 including delivery, the knock-offs and KCNC are more like £30. I've got a Hirame, and it was indeed more expensive than the rest of my SKS Rennkompressor but it changed it from a £50 paperweight into a useful tool as far as disc and H3 inflation duties are concerned.