My personal choice would be an 8' Sno-Way for that truck. That's based on quite a few years of using Sno-Way. They are much lighter than other brands, so are easier on the truck suspension. They have downpressure that more than makes up for the light weight when it comes to scraping clean. We just upgraded the plow on our 97 to a Sno-Way Vee plow and will now use both of our 8' units on our S-10s for this winter. By the way, is your truck long box or short behind that extended cab. If it's a long box you might consider going with 9' plow instead, that way your rear wheels won;t be treading in the snow every time you plow a corner.
I just looked in the new Sno-Way brochure, 9' straight blade with mounting kit comes in at 660 lbs. I think that is comparable to Fisher 7'6" but sure givesa lot more clearing width. 9'1" Vee is 822 lbs installed so not all that bad either. I think the Sub only comes in a LD version, not the heavier 8600 lb model. Six bolt wheels are LD, HD models have 8 bolt wheels
I know in places that get a lot of snow that 3/4 and 1tons are the standard for heavier plows, but I do have 1 truck that is a 91 1/2 ton pickup with (wince) a v6 and a 9'2" boss. I have had this truck set up this way for three years and it has worked great even on snows of 8" or more. Three more of my big boss plows are only on 3/4 tons. So I would say tha tyou have plenty of truck for any thing you want to put on it. Oh also I have Timbrins in the 1/2 ton.
I got an 8' Dimond with the out front electric.It's done a very good job for me in boston.Don't buy the front curve from the dealer,secret is to get some used converour belt for it.It just right to bend over for the curve to keep the snow from flying over the top of plow but you can also pile with it too .You can't pile with the stell ones from the dealer.