Here are the Win Relative Frequencies for various weights both carried and allocated. Sample 1.9 million.

Weight and Win Relative Freq.
Weight Carr.. Alloc. Weight ...Carr..... Alloc.
50 ... 0.501 ... 0.518 ... 56 ... 1.212 ... 1.170
51 ... 0.627 ... 0.508 ....57 ....1.386 ....1.349
52 ....0.651.... 0.512 ....58 ....1.451 ....1.428
53 ....0.692 ....0.602 ....59 ....1.549.... 1.566
54 ....0.802 ....0.761 ....60 ....1.557 ....1.556
55.... 1.044 ....1.003 ....60+. 1.272 ....1.292

55 kgs is the "advantage limit". Of course it doesn't mean that <55kgs can't win it simply provides an indication of the size of the advantage.