Following 9 months of research I became more aware of what I wanted and what hardware was available that I initially believed I could reasonably use to pull it off with:

Redraw rate of 60 Hz for one screen, 30 Hz for two. This is independent of screen refresh rate which is 75-150 Hz

Connection with OLED display over SPI

160x128 OLED display with a screen size of 1.8" or 1.56" w/ 65K colors displayed

Metric gauge faces for 1.5 bar, 2 bar, 3 bar, and 6 bar for diesel applications

Metric gage face for vacuum to 1.5 bar for petrol applications

Imperial gauge faces for 25 psi, 30 psi, 45 psi, and 85 psi for diesel applications

Imperial gage face for vacuum to 20 psi for petrol applications

PIC32MX695F512H MCU

100 psi, 0.25% error tolerance, absolute pressure sensors for Intake and Exhaust manifold pressures

10-bit A/D creates sensor resolution at ~0.8416 kPa or 0.1221 psi.

30 psi, 0.25% error tolerance, absolute pressure sensor for petrol IMP

Connectivity for K-type thermocouple for EGT readings

Electrical taps for stock IAT & MAP sensors of the 2.5 bar, 3 bar, and 4 bar variety.

User selectable colors for needle and gauge faces

Color choices for startup animation

2-board design. Primary board containing MCU & display hardware. Secondary board containing the breakout for sensor connectivity

Support for up to 7 sensor inputs such as: Boost, EMP, IAT, EGT, Oil Pressure, Oil Temperature, and Coolant Temperature

For top end model with logging capabilities, the requirement of a speed sensor via the bell housing of the transmissions will be in place

Logging will autonomously be initiated by user holding engine speed at 1500 (user adjustable) RPM for 2 seconds

Logging will cease when idle has been detected for 5 (user adjustable) seconds

Log files written in CSV format over USB or to microSD card to be downloaded later

Logging rate of all sensors at 10 samples per second, though adjustable from 1 sample/sec to 100 sample/sec.

When rapid acceleration has been detected via speed sensor or rapid increase of boost/emp, the all tick marks other than a whole number (Metric faces only) or those a multiple of 5 (Imperial faces only), will be faded to black in a manner that indicates a trail following the needle's sweep.

Ambient air pressure sensor with altimeter

Boost and EMP will be actual pressure greater than current air pressure. Ambient air pressure will be determined as a running average over the prior 60-65.5 seconds. Differencing can be disabled.

Artificial inertia added to needle movement.

Boost and EMP samples are taken 500/sec and averaged to across a running 32 ms buffer

Maximum EGT & Boost readout. Method of display has yet to be determined

Separate "Diagnostic" screen to display numeric & converted readout of the 7 data collecting and 2 relative sensors.