Making seat brackets/mounts

[Nova70]

I got some seats from an '05 GTO and want to put them in my '70 K10. I have the seat rails from the GTO, the seat is all electric but I'm not sure about how to approach making some brackets to raise the seat. Should I just pick-up some square piping and make a box that will sit between the floor and the seats? How would I make sure the seat is squared in the cab also?

Edit- I also have a bench seat currently and going to be putting my tank under the bed before doing the seats. Thanks for any input.