Mytee jugs are super heavy duty, and have a large fill hole as well.
I have both, since you specified Spraymaster I just gave you their link, sorry I did not give you both links. .Spray master is 7 quart, Mytee has both the 5 quart and a 2 gallon size depending on your prefference. www.mytee.com
Simple... with all the mytee advertising and support of the board with the MikeFest5... you would think these yahoos would know where to find those big blue jugs with the fill hole on the rear! Kinda of embarassing actually that it took 6 posts to figure that one out!