hahahahahaha excellent very funny
On a serious note, I have ordered the Chamonix reflex viewer. I never got used to/much liked the upside down viewing thing of 4 x 5 and apart from the heat, 'the sweats' can come at any time and in any weather!!! haha I will see how I get on with that first. I like the intimacy of viewfinders with cameras. Thanks for all the comments and of course they are all welcome and relevant as I will order a 'dark cloth' just in case.
If the heat comes a an issue, perhaps a cooler, first choice, with some sealed chemical freezer cooling packs or a grocery's to isolated, zipper bag with handles, second choice, for your dark cloth in hot situations, will allow you to work more comfortably.
When using a changing bag on hot/high UV or bright days, it may get better handy to use your white sided dark cloth as a cover over your bag or tent to help you not to instantly have sweat covered hands, making things more difficult.
You might even be able to develop in the 'field' like this.