Well, if you're concerned about losing the clock, then just buy a new Headunit, one with a clock. However, if this is not an option for you, then the "baffle" you're talking about sounds like a good option. Regardless of which you decide, you must have an accurate Boost and EGT gauges. If you have a spot for a third, then Oil Pressure or Oil Temp is another good choice.
I went with Greddy Electronic gagues..... they are some of the best on the market. Blitz makes good gauges as well..... there are some others out there. Personally, I would stay away from Autometer or any of the other cheaper gauges out there. A gauge is only as accurate as the sensor it uses, and Greddy has some of the best.