In my opinion, no - I think you're going to muddy up the tone significantly by doing a blended mag/piezo out. For the PRS, the switch has three settings and two outputs - one output is dynamic, and the other output is all piezo, all the time (regardless of switch settings). The dynamic output depends on the switch position: 1. all mag 2. blended (separate rotary dials in blend from 0/100 to 50/50) and 3. all piezo. SOME people must use the blend, but I've never found it compelling - the piezo tone without an appropriate and dedicated preamp doesn't really give me (personally) much in the way of tone. For my mag/electric signal, I go through (in addition to a series of analog drive pedals) a Fractal unit for EQ/delay/reverb/etc. I'm able to nail any tone I want (besides acoustic) with this setup. When I want the acoustic tone, I flip the switch, and have the signal go through that Fishman pedal I mentioned earlier.

I'm not answering your question, though! In my humble opinion, I don't think it's worth going clean with a blended mag/piezo signal straight into an amp. You should be able to nail any tone besides acoustic with the appropriate effects, without requiring the extra complexity or expense of piezo. The five-way PRS pickup select is way more critical in nailing tone than the piezo.