Q : What is the normal metric size of a monster anyway?
A : I found some informations :
the monster is 22m-72ft high and 41m-134,5ft long (with barrels).
So a 1/48 would be 47cm-18,5" high approximately and 85cm-33,5" long !!
1/60 would be 36,6cm-14.4" high and 68cm-26.7" long
note that the VF-1J is 12,7m-41ft high in battloid mode. 1/48 is 26,5cm-10,4"