the only person I know that is in your class, Dave, when it comes to Googling is my son. A valuable skill!
I think that Ashcroft gauge was a 1% gauge and it cost me something like $60 12 years or so ago.
Hot wire set ups are dead easy to do, but the after market prices are reasonable these days.
http://www.turbotweakstore.com/ProductDetails.asp?ProductCode=1014-BuickMight be worth the time to do it in some cases.
I remade one on Sunday. used a 10 gauge maxi fuse holder from the back of the alternator to a 30 amp relay on the inner fender (replaced the in and out terminals on the relay with 10 gauge terminals)...ten gauge wire to the back of the car where I spliced into the pump power wire.
Triggered the relay off the fuel pump test connector under the hood. Dead simple.
The one in the kit mounts the relay under the car and triggers it with the original fuel pump feed. It is nice and professional and costs $45 which is not too bad when you consider the effort it takes to make it.