Breeding is more than weight it's a combination of weight, age and proper proportion and feel, going on 2 years and just 1259 grams is not something I would breed.
I would breed a 1200 grams past 3 years, I would breed a 1500 grams over 18 months but would not breed your female.
What's the rush?
Nope at that size she does not need 10% or 20% of her body weight that's way too large of a prey item you are talking about feeding a rat up to 250 grams even my 3500+ grams females never get rats that large (they max out at 120 grams rats). You feed a rat that large not only will she become an inconsistent feeder but she will fast too, and if she does not, eating at that rate will get her fat not plump and likely to slug out among other things like fatty liver disease which has been seen in BP.Feed her rats weighting 10-20% her body weight weekly. She may plump up in time.
There is a difference between a plump female and one putting on too much weight too fast.
Sight I will never understand why people are in such a rush, grow your animal at their own pace, breed them when not only they are ready but when it the OPTIMUM time to do so.