Using 5932/6L6WGB wide base tubes in a 5F4...

[Cobra]

I saw some 5932/6L6WGB tubes on ebay, & in the description it said to make sure the spacing between octal sockets is enough to accomodate the wider than standard bases. Since these are supposedly ruggedized Mil-spec tubes, the auction got my attention. Has any one used these tubes in a Tweed, & if so, do they fit, & how do they sound?
Thanks much!