Hi Blandy.
You could use both the almuten and general ruler, but would this not make things more complicated than is necessary?
Then again, perhaps there is insight to be obtained from it.
For example, imagine that there is something interesting going on between these two planets, such as an aspect, a reception or both. Surely then this is telling us something interesting about whatever is represented by that cusp. Especially if the nature of the question concerns that house cusp in particular.
So I would probably say, that if the cusp is relevant to the question, and especially if there is something interesting going on between the two planets concerned, then probably yes, but if not, then it may just serve to confuse, in giving us more variables to consider than are necessary,
I suppose whether or not it would be necessary to do this would depend upon the nature of the question.
Did you ask this in reference to a particular chart?