We can say after the first day (yesterday) of working with the new scale that the hardest part is not getting any of the cats onto the scale. Rather it's keeping the other two cats off the scale while the current subject eats his/her kitten treat during their weigh in.
Even Emily didn't mind being picked up to be set on the scale. (Well, she did mind a little, but was perfectly calm once placed on the flat scale with a treat.)
The boys didn't need to be picked up, they were happy to follow the treat up to the table holding the scale.
Had we known it was this easy (and relatively affordable), we would have bought a scale for the kids a year ago.