Try bag rooting... it is best way to root the plumeria.

Good luck,

https://southerncaliforniaplumeriasociety.com/bag-rooting-methods/

Lol...it's too late to try bag rooting now on this particular cutting ;o), it's already been 5 weeks since I have started rooting this in a cut clear plastic water bottle. Was hoping to get advise on whether to water now or wait another week from some of the experts on Plumeria out there...but thanks for your advise on bag rooting for the next cutting if I get another one...

I usually wait until the leaves are bigger to water. The trunk contains enough water to carry them through winter. Getting fungal issues while dormant is my primary concern when I do that.

I would water at 5 weeks.

Thanks! I actually did just that, I watered at 5 weeks and watered again 7 days later, not heavy watering...my rooting medium is very fast draining, lots of perlite and tiny pieces of orchid bark. It must be doing okay as I have one large leaf that has emerged and a couple tiny ones coming right along. Once it's 8-9 weeks since rooting, I will repot it in a 4-6 inch pot.

With that potting mix and the time of year here in the northern hemisphere, you are probably going to be okay with a sip regardless. If you have that large of a leaf, you're good to go for full water regimen in my experience. Nice job on rooting a 12" cutting! Smaller ones can be more finicky. What's the flower?

-s