Envelopes for 5" x 7" cards

Often when I make 5" x 7" cards, I'm starting with a card base that already has a matching envelope.  Sometimes, however, that is not the case, and then I'm faced with a challenge.  I love my Enveloper, but it requires the use of square paper.  In this case, one that is 9 1/2" x 9 1/2".  Since most paper I use is 8 1/2" wide, this poses a challenge.  I can either sacrifice a piece of 12" x 12" paper to the cause and cut it down to size or . . . . ?  

Since an 8 1/2" x 11" sheet of paper should be wide enough for a card this size, I finally broke down & worked on making an envelope from a standard letter size sheet - recording sizes so I won't have to do this math again!  I drew these measurements up and scanned in the picture.  

Unfortunately, this resulted in a document that is harder to read than I would like, so I'll call out the measurements again as I describe my method (though I think if you click on it you'll be able to see it okay):

1. Using your score board, score each long edge of the paper at 5/8".
2. Turn the paper 1/4 rotation (rotate picture to the left), then score at 3 1/2" and 8 3/4" (this is 3 1/2" from left edge & then 5 1/4" from that 3 1/2" score line).
3. Cut away the four corners along the score lines.  This means you'll cut away 2 pieces that are 3 1/2" x 5/8" and 2 pieces that are 2 1/4" x 5/8".  Now you can fold along the remaining score lines (dotted red lines in above picture) and round all corners if you wish.
4. Rotate so paper is in portrait mode with largest (3 1/2" section) towards you. (See picture below)
5. Fold narrow sides in along score lines, fold up bottom portion along score line.  Crease all folds well & then glue bottom portion to the narrow sides that have been folded in. (See picture at the top of the post.)
6. Remaining flap will be closed after the card has been placed inside.