Agree with what said that female should be larger than male, but it is also tricky as they may have larger breed in their lines and can get bigger kits, even bigger than themselves so it is quite risky for mother and for her future generations because you don't know there's no record of who their parents/grandparents were so you can't be sure.
Bernie is a mix between mini lop and holland lop I believed, but half of her kits were much bigger than she and her male, they were large blue-eyed whites, giving birth was painful and risky, I only realised that now after she had more kits and three large blue-eyed whites as well, other kits were mini-sized and very different. So I would never breed her again because now I am quite sure it comes from her side, and her mini-daughter will also be fixed to prevent this. One her son is a beautiful classic mini-lop with fantastic personalities and very tidy, but again, if you breed him and you'd expect mini-kits it can be very wrong as he can also carry that giant gene, or his next generations. So he is also very risky I am going to neuter im as well.