If you are looking at an early 90's Cannondale, this could severely limit you fork choice, if a frame originally designed for headshok, unless appropriate adapters are used.

The range of 1 1/8th 26" forks out there that are light enough to keep the bike at your proposed weight are getting fewer every year, if you want light weight, would go with a rigid carbon fork rather than suspension, and look at higher volume tires to give some comfort, this should be cheaper, and probably lighter overall.