A recovery tank should be as close as possible to the level of the overflow nipple on the radiator filler as possible. I've seen the tank bracketed to one of the brace rods from the firewall to the radiator support. The less the suction in the radiator has to lift the coolant to refill the tank, the better. another good spot would be on the firewall at approximately the level of the top tank of the radiator.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!