The problem with just taping over the top holes, is that the thing then plays an octave too high - you need a Low Octave base whistle to start with for that trick - the REAL tabors are twice as long as a whistle of the 'same pitch'... and as far as I have found the 'traditional' Tabor pipe is pitched in G (thus would be a Low G)... :-0

but then I'm a TRAINED (sat formal exams!) muso, so usually can quote the Theory to back up what I'm talking about.... :-P