That would all depend on the size, weight and age of the animals at current. WHY are you fattening them is also a question in play. Get some pics of them for us maybe? Also, i doubt pinkies will be needed.
You should never "fatten" up geckos quickly on purpose, IMO. Feed them at a normal rate and let them grow at a normal rate. What genetics does he have? Do you have a female? Do you have a hatchling rack or individual setups for each new gecko? How will you feed a dozen new geckos?
Before breeding, honestly, spend at least a year perfecting your husbandry and hanging around here to see how it goes.
I'm about 3 almost 4 years in, and I am maxed out on what I can manage alone.
So this year, I'm scaling way back. There are already too many leos out there. It's not just a hobby, these are little lives you're putting out into the world. Please give it more thought, they live for a good while, and once they are out of your hands, you can never be certain of their fate.
Patternless stripe or murphy's patternless male? Is she a confirmed tremper sunglow?
I'm glad they're all set up individually now, but do you have a hatchling rack ready?
How long have you been breeding? I'm just wondering, since you're asking the kind of question you asked in the first place. I'm glad you're asking, but you can't just go out and buy tons of geckos and start breeding and make money. It doesn't work that way, not with leos. Why do you want to breed?
Katie, I would agree with you, but I had an adult female giant come to me 35 grams and gravid. We fed one pinkie a week, as a dietary supplement, to help her maintain weight. It wasn't every meal, but without the extra fat, she might not be here today.