The Painless one in Summit link I think uses a single screw to mount, I don't recall for sure.
Problem is normal ATC/ATO fuses only go up to 40 amps nearest I can tell.
There is a ton of multi circuit fuse boxes out there for those style fuse.
After that they go to the much bigger (physically) MAXI fuses at 50 amp but still in the blade style.
There is a couple more options maybe, depending on your gauge wire used.
One idea, this is a 6 position though. You can call or email them, they might have some better idea's than me. There good guys, make nice stuff and know there trade, even write their own books. They can build it for you too.
https://ceautoelectricsupply.com/pro...proof-pdc-kit/
Something like this too. It's a dual MAXI style fuse block. Kicker is it needs minimum 4 AWG wire on input.
https://ceautoelectricsupply.com/pro...dio-xd-fdbu-2/
Another option:
https://ceautoelectricsupply.com/pro...-xd-mfbw-maxi/
And maybe your best bet is this guy, just use two 50 amp ANL fuses.
https://www.sonicelectronix.com/item...use-Block.html