William
With all due respect, I would suggest that you are approaching this situation from the wrong direction. You shouldn't be looking for a 4 jet wand, rather a wand that works well for you with your machine. 4 jets will be adjusted to deliver the same/similar amount of water as a 1, 2 or 3 jet. IMO an 18" wand will loose too much lift to be of value to you. By all means try different wands, but remember that your physical size, shape and proportions can influence the tools performance just as much as the tool itself.
Safe and happy cleaning
Ken