Yeah their website is a mess.
That looks like it would do it for the most part. I think all those gaskets will work except the head gasket and the cylinder base gasket (would have to be trimed to clear the sloper cylinder liners I think)
$45 including shipping kind of sucks. But looks like good quality stuff. I know Athena used to make a set, I have the part number, some places it's listed as fitting 67-78 175's....other places it says 69-78 ...which wouldn't include the slopers. Only two gaskets are different...the primary cover and the oil pump, they used to include both varieties in the sets. Athena stuff is beautiful quality, top notch gaskets....but hard to get in the US.
Thanks for the link bro,