Here are the current default frequencies - can be easily changed in Patch_Xenotype_Bodytype.xml

Xenotype
(Standard, Thin, Hulk, Fat)

Baseliner / Dirtmole / Impid / Waster / Sanguophage
(Standard = 1, Thin = 0.15, Hulk = 0.1, Fat = 0.1)

Hussar
(Standard = 1, Hulk = 0.4)

Neanderthal
(Standard = 1, Hulk = 0.25, Fat = 0.25)

Pigskin
(Fat = 1, Hulk = 0.25)

Highmate
(Standard = 1, Thin = 0.5)

Genie
(Thin = 1)

Yttakin
(Hulk = 1)

is the bodygenedef file necessary? As far as i can tell, all it does is create identical duplicates of the body size genes which appear in the misc tab, and all that is really necessary is the genedef patch.