I had a 94 GMC pickup, but it was a regular cab. I had a VHF 1/4 wave on the roof and a CB whip (larsen NMO27) on the left front fender.
The 1/4 wave worked well, but the CB antenna was just OK. It was hard to get it to tune correctly on the edge of the hood like that.
I think with the longer length of the extended cab roof, you'd be best served by installing two NMO mounts on the roof, in lined down the center, and use one for the dual band ham radio and one for the scanner. While there are way to do it different, the center of the roof top is a better location, performance wise. On a pickup, you don't really have a lot of other options. The hood/fender mount may cause some issues with the cab blocking the pattern. Magnet mounts work, but I prefer to drill. Glass mounts are just weak at best, especially on the lower frequencies.