Chris,
I've never flown any military aircraft but have flown both a Lear 24 and the IAI Westwind. (it began life as the Jet Commander before the Israel Aircraft Industries bought it)There were limitations on fuel distribution between the wings and tip tanks. The Westwind, for example, had a limitation the didn't allow any fuel in the tip tanks on landing. Normally it wasn't a problem unless you had to make an emergency return after take-off and in that case the aircraft had the ability to dump fuel to reduce the landing weight and get rid of the tip fuel. I don't remember the limitations on the Lear tip fuel on landing anymore but it definitely will tip up on one wing with a significant fuel imbalance during fueling. I do recall 110 gallons was the limit before moving to the other wing but you got scared watching the wing go down as fuel was added long before that.