Hello,This is a pre-purchase question, so I'm new to Caseta, but not to residential wiring. I have a few locations that have 3-way dimmers with mechanical switches at the opposite end, and I'd like to replace the dimmer with a smart dimmer, but leave the original mechanical switch at the other end. My reasons, besides cost and device count, is that I have multi-gang switches installed at those locations, and I'd prefer to leave them intact.In the Advanced Installation Guide, all the references for use with mechanical switches reference the PRO dimmer, not the PD-6 dimmer. Is it required that I use only the PRO with a mechanical switch?As a related second question, is it possible to use a Caseta dimmer (PRO or not) in a 4-way circuit, as long as the Caseta is located at one end of the run? (In other words, I'm not trying to swap out an existing 4-way switch.) tia