When is the best time to take cuttings?

Maturity can matter. Younger plants may be difficult to clone. You need 'enough' growth to take a cutting, anyway, that you probably won't run into that issue. Alternating axial buds is definitely a sign of maturity, but it is not necessary. You should have near-100% success before it starts asymmetrical growth. I do a very simple process and most root. So there's no need to be super elaborate unless you want to set speed records or run a commercial business, lol. Humidity dome is definitely helpful unelss you live in a rain forest with 80% or higher RH etc. A heating mat is a great idea, too, unless you live in a warm climate already that will keep the substrate 76-80F etc. Do hormones cut a day off? Maybe. I don't bother. I plant ahead. An extra day or two is irrelevant relative to the resources invovled. Very low wattage is needed and a small space is not a burden worth investing a bunch of effort. Don't give it too much light... don't needlessly stress it... keep transpiration to a minimum with high RH% ... do that and you'll get roots fairly fast, and invest little to no time or stress... When you start see vege growth resume, you likely have some rotos -- not speaking of the slight growth that happens after taking a cutting... you'll notice over th efirst 3-5 days the leaves do continue to get larger at a snail's pace and maybe even a centimeter taller etc. When growth noticeably picks up, you'll know to start hardening them off -- more light, less RH slowly over time. for any video or reference that purports once location or timing is better than another you can find one that says the opposite. I've never worried about tops or lowers or night or morning.. it's still near 100% success as long as you control climate and don't try to give them too much light. You may come across a genotype that is more difficult to clone, but it should be rare... assume elevated failure rate is something in your own process if it's a healthy plant. --- Make sure it's a healthy plant to start, lol... if that common sense needs to be said, and adhere to KISS principle - Keep it simple, stupid.