Thanks for the update. I have been looking around on the net for something like this, and this looks very good.
I have a Hobbysport tractor with a friend. A Same Panther with 6 cyl 6ltr engine and stock it has prf1k90.... pumps in it( each cyl its own 9mm pump).
And they can't be made bigger, only good thing about them is that they start with 700bar can go up to 1200bar of injection pressure.
A Inline would be the first chose for many. I think that Common rail could be "easyer" to build, mechanicly than.
Only the hardest part for now is to find injectors that could fit with the least modifycations.
I found the Cuprum befor the arduino, only my electronics knowledge isn't so good.
Are you using a alternator to replace a rotary encoder? bit like this link Simple Rotary Encoder
Hope to see more here.