@Frenchman - I am dependent on using compression socks (along with compression base layers) due to health reasons, but I cannot imagine skiing without compression socks now that I've learned of their benefits whether you have health requirements or not.
I'm wondering how much compression the Lenz 6.0 actually provides as I cannot find a spec for the compression level on their site. I will say that careful and correct installation of normal footbed heaters should not result in any problems with fit and you shouldn't be able to feel any part of it (element or cable). Sidas has begun producing footbeds that are "heat ready" - they allow the element to be installed just under the top layer of the footbed so that you don't need to add any covering over the element. I've actually already been doing that for years by simply peeling back the top layer of the Sidas footbed's forefoot area and installing the heating element between the layers.
The original Sidas heating system used a fairly good sized element, but the rebranded Therm-ic system uses a smaller circular element (similar to Hotronics). I wish there was a larger heating element available that can cover more of the footbed forefoot area.