Carling doesn't supply mounting hardware
, that is an add-on that Blue Sea throws in, with the assumption you will be mounting their breakers in their panels
. Since Carling doesn't supply panels
, they have no idea how think the panel you will be mounting in, or the style screw you prefer.
If you DO buy the breakers from Blue Sea there is nothing that says you have to use THEIR 6-32 FH machine screws. You can replace them with screws you have full specs for. I am pretty sure that will not break the bank.