Would you recommend getting a set of 108ppsi carders as well at the 72ppsi? Does the finer carding eventually yield a finer thread in the spinning process? the 72 ppsi is a great versatile hand carder. The 108ppsi is only necessary for fibre with a micron below 18 (lambs wool, angora, cria) , so if you have a low micron fibre then the 108ppsi would be necessary.
Fine carders are used for carding finer fleeces and the 72ppi would be too strong for the fibre and would damage it.