When I bought my Herbert 0V I replaced the spindle taper with a 4MT, the main reason being that I had 4MT tooling from the mill the 0V replaced. I finished the taper exactly as Pete R described. Not that easy to do but well worth the effort.
With hindsight, I would have preferred to use a 30INT taper. The advantage of the International taper is that its not self locking unlike a Morse. Both Morse and International tapers give a far more better location than R8. Also, R8 mountings are known to wear on the parallel diameter with the inevitable affect on accuracy. Providing the mounting is accurate in the first place I don't think that will be a problem with the amount of use our machines get!
Incidentally, I replaced the existing bearing arrangement with tapered rollers for a more ridgid support of the spindle. Doing this enabled me to reduce the overhang of the tooling and gain a little more vertical capacity.
I have an electronic copy of the manual for this machine, if the OP wants a copy let me know.