Implementing dynamic poly~

I've read many times that 'dynamically loading patches' into poly~ will make my life better, but until now have never actually had to do this myself. Nor have I ever actually seen any concrete implementations of this technique on the forum.

Attached is my basic stab at doing it. I'm not convinced it is 'guarenteed safe' from clicks. Can anyone offer any advice/improvements on the attached implementation (a zip containing the parent patcher and three basic poly subpatches) or alternatives methods.

Specifically, I want to be able to duck the volume of poly~'s output whilst loading subpatches (to avoid clicks) in as neat a way as possible. Knowing when to bring the volume of poly~'s output backup relies on knowing exactly when the chosen subpatch has finished loading. Is loadbanging thispoly~ sufficient (from a dsp poiint of view)?

Would I be better doing the ducking within the poly~, or does this have implications if I want to mute voices?

Ideas appreciated...