Hoffy, regarding the changing bag, it's just too hot and sticky to use one of those in this part of the world now!
Wait until night falls, pick a darkened room, sit in a wardrobe on a small footstool and use a normal chair as a table.
You only require absolute darkness for loading the film into the tank.
Changing bags generally, or at least the ones I have owned and use and still own and use, are sort of moisture tight, as well as light tight.
Everyone I know in Oz with changing bags will tell you their sticky story of summertime film loading.
If you can, try for a wardrobe, or a like situation right now.
Mick.