Porpoising is generally an indication that the nock point should be adjusted, in bows I am familiar with (which doesn't include Hungarian horse bows). Generally, you would start with a nock point that you know is too high, and shoot bare shafts. Gradually move the nock point down until you minimize the nock-high arrow flight of the bare shaft. "Minimize" is the operative word, because you may not be able to eliminate the nock-high, and you don't want your nock point too low. Remember that "nock high" translates to "nock high and right" for a RH shooter who cants his bow (or just hold the bow vertical when testing).