Dave M makes a good point. Although I don't think that the water coming from the DT would be barron (not Dave's words), it certainly could have reduced levels of trace elements that water changes with freshly mixed saltwater have higher concentrations of.
I would consider doing what you're doing, but maybe also supplement the DT water (going into the QT) with a gallon of freshly made saltwater. That should probably be more than sufficient. But honestly, it probably wouldn't matter too much, but since you want the QT to "thrive", this would be the only thing I would consider changing about your plan.
As for your original question though, I would say that with the 35% of weekly water changes, along with any biological filtration you have (i.e., maybe a refugium with live rock or something) and minimal livestock, that you should be more than covered from the filtration department, and thus, no skimmer really needed.
Also, dosing would probably not be necessary, since, if I understand you correctly, you'll be doing daily water changes that will have the optimal levels of Ca/Alk/Mg coming from the DT.
So I think I just saved you some money there!!! I'll send you a PM with my information so you know where to send the check (kidding)
All in all, I think its a great plan, and a great way to reduce the maintenance of keeping multiple tanks!
Hope this helps,
Chad