Replacement Stepper Drives for Replicator 2

I got my hands on a Replicator 2 and the MightyBoard Rev H with a missing botstep and 3 blown BOTSTEP17Es ($50), so I went the Pololu 2128 S4988 Stepper Motor Driver, Black Edition ($6.95) with the 68mΩ sense resistors, which is the version made since Jan 2017.

I took voltage measurements of my working Rep 2s (Mightyboard Rev G & H) and carefully studied the schematic and datasheets of the A4982 (Botstep17E) & A4988 (Pololu 2128) to determine the following conclusions:

1. MS1 & MS2 are given +5V on all BOTSTEPs, which means the Mightyboard is doing 1/16 steps. MS3 on the A4988 should also be tied to +5V.

2. The Z motor Botstep's Vref into the A4982 is being fed 0.70V (Mightyboard Rev H). This equates to an Imax of 0.33A. Mightyboard Rev G measured 0.73V => 0.34A.

3. To get Imax on the Pololu 2128 (Jan 2017 or later version) to be 0.33A, adjust the potentiometer to 0.18V.

4. The X, Y and Extruder motor Botstep's Vrefs into the A4982 are being fed 1.68V (Mightyboard Rev H)