Here is a weight comparison I did a while back.
Crane solid body roller pair: 239.3 grams
Comp solid body roller pair: 268.5 grams
Magnum rollers: 303.2 grams, I weighed 2 together for comparison.
The Magnums were new replacements by Melling with no oil in them.
Going by this, 1 mag lifter is 32 grams heavier than 1 Crane, 17 grams heavier than 1 Comp.