Tj, I have to say that I've never used that particular LV but I don't see much point in paying so much for an LV 25mm. A 25mm Plossl will give you the same FOV and similar eye relief. So either save some cash and grab a 25mm plossl for less or get yourself a widefield EP. Some options: GSO Plossl for a fifth of the price, Antares Elite for 1/2 price, Televue Plossl for 3/4 (all worth the price). But for your scope at the price level of the 25mm LV I'd be looking at the 17mm Hyperion. It would be a great general purpose eyepiece for the 6" Dob, with a very nice much wider apparent FOV and only little less true FOV. Would work a treat at f/8.
As for the 8mm, that is where an LV could serve you well. Or you could again go another Hyperion. But I would not expect you'd get much out of it in a barlow - too much power. Better off with a 12-13mm IMO. 13mm Hyperion perhaps. Would make a great second closer-look DSO EP too. If you can spare the extra $$ for LVWs, they are worth it too. Don't forget to haggle for best price.
