Thanks, and good luck for those cuttings, Bob.
Some of those seem a bit long, but it can be the picture. I try to keep mine more compact, so they don’t stick too much out of the pot, when leaving the coco coir, or i have to place them too low on the pot and the young roots stay too close to the wet zone until they have time to adapt.
The cuttings on my video were started 8 of November and i removed them 1 of December (and place a new batch inside the same box as i show in the video), but they were, most of the time, over a glass lid of a heated aquarium, so the ‘hot feet’ accelerated the root development (usually is, at least, 1-2 more weeks, minimum)
Regarding the pen. I used Sharpies and they are not has detailed and don’t last as long as the ones i use now. These are from Edding (a German company) - https://www.edding.com/products/edding-8055-outdoor-marker/
I usually use the 8055, but sometimes i can only find the 751 (the one i used in the video) or the 750 and these also do the job. Don’t know if they are available on your side of the pond, though.