Cyc jean E Monnier, when to start water

[WillisWill]

Hi I recently picked up a Cyc Jean E Monnier from SVO. I understand that it's best not to start watering until the roots are a few inches long, but how am I supposed to know how long they are without taking it out of the sphagnum and totally repotting? can one correlate the size of the new PB with the size of the roots beneath?

Hopefully the attached pics show what's going on. There are a what appear to be a few new roots developing, that are maybe 1/8 inch long at the time. Of the newly developing PB, the bigger one is ca. 1 inch long

Thanks