I can understand people having a preference for the decimal numbers they're familiar with, but I'm not sure that it helps in this case. The numbers which you enter in the 00 box are two digit numbers, and the second digit must always be 0 or 8. So start off with a middling value, say 50, then resync and see what downstream noise margin (SNRM) results. Depending on this result, try higher or lower values until you get the result you want. Smaller values give you a lower noise margin.
As a rough rule of thumb, a change of value by the smallest increment, e.g. from 50 down to 48, will change the noise margin by about 0.5 dB.