Go up 8 inches, then over one inch. That's 1:8. I know some people mark it all out on the back of a bench hook and then they set the angle with a sliding bevel. I just bought the Veritas dovetail saddle markers.
The only Wen thing I have is an air cleaner hanging from my ceiling and it works ok for what I use it for... tools.. I'd stay away from, like the others said, at those prices, for slightly more you can get some quality tools that will last a lot longer. Just like harbor freight, you can find some useful things... but most of it is junk... or slightly better than junk lol.
I have one and love it.. and I rarely need anything bigger, when I do, I have a neighbor with a monster planer and drum sander. But other than that, the 735 does what I need it to.
Traditionally 1:6 for softwoods and 1:8 for hardwoods. The argument is to use the wider tails in softwood because softwood compresses easily and they could "wiggle loose" over the years, and use less wide tails in hardwoods because hardwoods tend to be more brittle and a wide flare could cause the "corner" of a tail to break off.
Ultimately I don't think it matters much structurally. But I like the look of 1:8 and I use hardwoods exclusively, so that's what I use.