The jointer technique for making wedges is simpler than that, even. Here's what ya do:
The finished wedge will be 5" long, right? So make up a little push block with a heel only 1/8" tall (because the narrow end of the wedge is 1/8" thick).
Mark out your wedge shape on the board, with 1/8" at the end and 3/4" at 5". Draw the wedge profile right on the edge of the wood so you can see it while you're jointing. Make a mark at the 5" point.
Use a strip of masking tape (blue, since it doesn't leave residue) on the jointer's fence directly above the cutterhead's centerline to show you where that centerline is.
Set your jointer's depth to whatever depth you can comfortably take off in one pass (1/16", 1/32", whatever you're comfortable with).
Lay your stock over the cutterhead, with the 5" mark directly in line with the masking tape. The bulk of it should lie on the OUTFEED table, overhanging the INFEED table on the 5" end. Line up the 5" mark with the masking tape.
Hold your board down and start the jointer.
Now tip up the long end of your board (over the outfeed table) until the 5" end barely touches the infeed table. Using your push block, run it through tipped up like that. It'll take off stock in a wedge shape, with the thickness removed at the narrow end equal to your depth setting.
Back it up & take another pass, exactly the same way. Continue repeating until the end is 1/8" thick.
Take one final pass to clean up the tiny step you made at the 5" mark. At this point you should have a very good wedge, 5" long, 3/4" thick at the 5" mark at 1/8" thick at the end.
Here's what you're doing: