Remove muffs, scat tubes and valves; replace with a length of wire and a power jack to plug your heated vest and insoles into. I'm just up the road from you and it works fine for me and my wife.
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.
Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65