Mixing the teas and simmering them down as you suggest is fine. It will still work considering ayahuasca is a single beverage - although there are important differences when one looks into it a bit more deeply.
This information is highly informative in this respect, and some recent posts
here link to key information on the subject, particularly the
article by Gayle Highpine.
If you are intent on rounding it down to a single beverage, you might find yourself deciding to take it in two doses, separated in time as before. Otherwise you could stick with the plain rue tea as the first dose, followed by the mixed brew 25mins later. Either way, you'll be able to dial it in nicely - starting low and building your way up, of course!
“There is a way of manipulating matter and energy so as to produce what modern scientists call 'a field of force'. The field acts on the observer and puts him in a privileged position vis-à-vis the universe. From this position he has access to the realities which are ordinarily hidden from us by time and space, matter and energy. This is what we call the Great Work."
― Jacques Bergier, quoting Fulcanelli