I have a 91HDJ81 and one of the first things I did was installing the Nomad valve body as I was planning on running a GTurbo. I don't have experience driving a stock A442F to compare but I have noticed many people drive in D all the time. That does not work well as it's the overdrive. I drive in 3rd until i"m on the highway and then upshift.
The valvebody is easy to install and comes with instructions. A tranny shop shouldn't charge you more then a few hours as it's all done with tranny on the truck. The price does not include shipping to Canada and shipping your old valvebody back to them as they want the core. 1Aus$ is 0.88Canadian$ so your $6000 estimate will end up more like $3000 if a shop does it and cheaper if you do it. Valve body AUs$1200 = C$1054 right now.
I’ve been told the nomad is not as harsh shifting as the extreme. Well worth it as a mild upgrade!!!