1992 240

I recently moved my 240's aftermarket cd deck downstairs out of personal preference, so i picked up a turbo gauge set on ebay to help me keep tabs on my engine and electrical system (and extra retro value for the analog gauges!)

I received oil pressure, volts, turbo, and mini clock (I replaced my large clock with a tach about 4 years ago), and I put them in their places, but have yet to hook up any of them. I've done a fair amount of reading on the boards, so ive got the jist of installation for the volts, pressure, and vacuum (turbo) gauges, but I have a couple questions.

(1) Is there any reason i would not want to just install the turbo with some of the vacuum tubing that is sitting behind the front console (im pretty sure i see some unused vacuum tubing waiting for a gauge back there) and use the turbo gauge as a fuel economy gauge? (if anyone has a spare f. economy gauge for sale, drop me a message)

(2) I believe i need a new oil pressure sender (1992 240s dont have duals already in them, do they?) to show incremental pressue, but do i need to get a sender specific to my 5 bar gauge?

(3) Its been a few years since i removed the clock from the dash and put in the tach (different finish, of course), and i went looking for the formally used wire(s) in the harness behind the instrument panel from the big clock, but couldnt find any unattatched wires...how do i go about installing this clock?

(4) Does anyone have a oil temp gauge/sender i could buy from them?

(5) If i give the boot to the turbo gauge and/or clock, would it be worth installing an ambient temp, fuel economy, or any other gauge available out there?

thank you everyone!