I personally would say imo it depends on more than weight. Has you gecko been well supplemented (calcium/vitamins etc), is she healthy?(if she's infested with worms etc. after she breeds it could be hard/impossible to put weight back n or even lay eggs.) eating well? fully grown or pretty close? (for example giants may be 60 grams, and technically ready to breed but may only be 5 months old and 1/2 grown) with all those factors aside there's been much debate on this subject. In the leopard gecko manual it gives an oddly low weight. Personally I wait untill they are a year old and at least 55 grams.
This is all just my oppinion others may have success at other weights/methods etc thats just me looking out for the safety of my babies.
Low 50's could work as long as you're confident she'll have no issues eating during her pregnancy & putting weight back on after the clutches. Personally, I don't see any need to breed before 60 but there are circumstances where a gecko tops out at 54 or 55 grams (around there) and it isn't wrong to breed at that weight as long as everything else is fine.
I agree 60 grams is best. But one of my original stock of normals I had a normal who never got above 52 grams. However the others which I still have all of them are 65-85 grams. So if you've had a gecko thats in good health but never reaches 60 grams after about 2 years I'd say it's ok to breed imo.
