Double Clutches

[MouseKilla]

This came up in another thread about the age of adult snakes. Mark I. was referring to ideal breeding size or age for female corns coming typically in their third year (I think that's what he said... don't wanna misquote...). He said this way they've grown into big double-clutchers. My question is what is the general threshold for size when considering going for that second clutch? Is size the only consideration or is it a combination of size and age? What would be the minimum body weight at which a second clutch should be considered?