R9920 Rugged Shoulder Bag from Ten Tec for FT-857

My FT-857, battery, coax, and a piece of sleeping pad foam (to protect the 857 control head display) fit nicely into the R9920 Rugged Shoulder Bag that came with my R4020 from Ten Tec. (I love the R4020 BTW!) What do people think about operating the radio /PM from in the bag? My concern is: will it build up too much heat and damage the radio? This would really trim down the bulk in what I carry for SOTA. The antenna will be a stripped down Buddistick / hiking staff. Not quite a manpack radio, but getting there…

Any thoughts?

Thanks!
KB3UYT/Eric…