I have the AT72ED scope (430mm f/6) with 2x barlow lens and two plossl eyepieces (25mm and 10mm). I would like to buy one more eyepiece (lower than 10mm) to get more magnification but I am not sure what would be the best one to get. I am assuming that around 140x is the maximum I can get thru the scope so I am considering 8mm, 7mm and 6mm eyepieces. Each will give me over 100x magnification with the 6mm reaching 143x.

Any recommendations?