Engine and trans positioning for optimum pinion angle?

I've gathered up everything I need to start installing all of the motor and transmission mounts in the 65 AWB Coronet. RB block with Ansen bellhousing and an A-833 trans. Rear suspension is forward 19" and front axle is forward 12". Being built as a AWB car with no regular racing planned.

Right now the car is sitting on a jig almost dead level front to back (.02 on a digital level)at the rockers and frame rails and dead level side to side.
There's really no way to know right now what the exact front and rear ride height is as there isn't enough weight on the car to find out.
The front end is a straight axle with leaf springs. Rear is an 8 3/4" with SS springs.
I'd like for it to sit typical to a 60's AWB car with the front end higher.
The only original mounting point of the engine that's left is the Z bar pivot at the base of the firewall.
I have the correct Z bar and pivot for the Bellhousing.
Should I mock up the rear suspension to a dedicated ride height at which the car will finish at...then align the motor and trans thru an imaginary line ran forward from the pinion through the trans to the center of the crankshaft?
Front U Joint at 0 degrees and then set final pinion height 3-4 degrees down once the engine and trans are in place?
Is there a better way to determine the correct engine position? (Nose up or down)
I will probably never competitively race this but don't want to install this wrong when I can move it and make everything correct.
Thanks for any and all input and lets try not to turn this into the typical pinion angle argument...

Front frame rails and suspension...

Wow - that's cool !

Your gonna want to to figure the ride height.. basically
the rear of the car... point the engine trans directly at
the pinion with the pinion on that center line... I made
a laser set up that points directly through the pinion
center line... once your done then you roll the pinion down
to get your angle... move the engine to line up on the center
line with the pinion.. your gonna be changing both the pinion
center line and the engine to get the correct location.. I
assume you might use a front motor plate so it might go up or
down to get it all in one plane.. also figure that the higher
the engine is that it will transfer weight easier.. big torque
engines dont need to be high(big wheel stands)

We're thinking along the same lines. Engine should be decent but not a torque monster. Since the front rails are much lower than the stock ones everything may move down inline to avoid tall wheelstands and not enough torque to drive out without it coming down hard. That's as easy as modifying the z bar pivot at the bell. Thx...

After you get the location of the engine/trans and the
angle then IF you need you can weld a plate on to have
the Z bar level on the bar so dont figure that yet
EDIT
I made up a laser mount to mount in the #5 main cap of
the engine.. I zeroed it in my lathe so it was true(had
3 set screws to zero it in)... it was just a laser pointer
that you can buy... works great