cw,
I don't think the fluid is "Sweating" through the hoses. I think it's eating through them. Some rubber materials will not stand up to some brake fluids. You don't say which of either you're using, but obviously you haven't found the correct combination!!
Tilton engineering sells various master cylinder kits which include remote resevoirs as an option. They come with rubber hose. We've never had a problem with them. I suggest you contact Tilton and ask for their advice or perhaps their hose. Cheers.
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon