A temrorary nock, or a second nock for a stringer (only needed on one end, with a deep er groove at the other end) takes very little time or wood, I've cut stringer grooves1/16" from the end straight into the back of the bow (Yew warbow, no problem). Or filing a slight flat and a temporary overlay is also no problem as it will get removed when the final nock is fitted.
It's easy to save 5 minutes work by messing about for half an hour with a shortcut!
Del
PS, in the early stages of tillering you want to leave a little extra wood on the tip to allow for string line adjustment etc... so there should be enough spare wood to file in a couple of grooves.