For me, to do a DT on my very dry hair, I put on my conditioner, plastic cap, then sit under a hooded dryer, using low or medium heat, for approximately 35 minutes. I then rinse with tepid to cool water. I have tried other methods with heat, but this one works 100% of the time for me. I no longer have a problem with dry hair, including the ends.
I also use a moisturizing leave-in prior to other products and styling. And, I wear a satin cap to bed.
If you would like to try heat with your DT, start with 15-20 minutes. Try sleeping with a satin bonnet or silk (or satin) pillowcase, if you prefer. See how your hair feels afterwards, including the next day. You'll then know if you need a leave-in conditioner.
You have some wonderful suggestions so far; I'm sure you'll receive some more. With some trial and tweaking of the ideas, your dry hair days will be over soon!