enduro wrote:s I will be taking will be mostly synthetic Gortex lined Salomon GTX boot which is light and appears to transpire well. I do have leather boots, but they are normally so heavy I choose lighter boots nowadays to save my knees.
I've hiked all this summer in some GTX boots (~350km over Dec,Jan,Feb). Salomon Fastpacker GTX. I was given a replacement pair around May-June, and I've been trying to wear them out before the warranty runs out.

Hasn't worked, nearly at 1000km they're holding up well and I think they'll last out the year.
Anyway, after 5km or so I have removed the boot and sock, both dry (well, to be accurate, not wet) there's always some perspiration but it doesn't seem to have been building up in the boots or socks. Socks are X-Socks "Lite Hiker" They're synthetic and good. Imported from UK, prices here for X-Socks are crazy.
So, if you're comfortable in those GTX boots of yours, I'd be inclined to use them with a good synthetic sock and let the GTX sort it out.
BTW, the GTX works in the Fastpacker. I stood in a river with the water just below the top of the boot for a few minutes, and there were no leaks. Like all boots, once I actually walked through the river it took quite a while for the boots to dry, the foam lining around the ankle absorbs water.