On page 5 of the manual it clearly states that you can use spade lugs. It doesn't however state the size. I don't think I've been much help with that little tidbit but here's the # for Lenbrook in Pickering Ontario (Owners of NAD, PSB): (905) 831-6555 , not sure if it's the same # you had or not, also there is a help centre on their website where you can email questions.