Well said by Brock

I think in terms of 1/4 division because that’s what my foot knows how to tap tempo.

Then I take the sub-divisions into account and apply the to the heads

1/4 is1/16 note

2/4 (input as1/2) is 1/8 note

3/4 is dotted 1/8 note

4/4 (input as 1) is quarter note

A dotted note is an additional half value of reference note length (50% more).

You can see the sequence of divisions from 1/16th note to 1/4, with the numerator (top number, 1,2,3,4) incrementing and denominator (bottom number, 4) constant. You can do the same to 1/6’s for a space echo feel: 1/6, 2/6, 3/6, 4/6, 5/6, 6/6.

i use +/- 3-5% to nudge the heads off from perfect to emulate a real world tape deck heads.