69 K20 6.2 Diesel Conversion Engine Mount Location

[The Youngen]

I just received my cab back from the paint shop to find that the 6.2 diesel is hitting the firewall.
Since modifying the firewall is out of the question, the engine must be moved forward. This is fine since the drive-shafts will be custom made and the transmission cross-member is still unbolted.
Since a 6.2 diesel is roughly the same dimensions as a big block, I assume i would move them to the "forward holes." F.Y.I. Im using the 69 engine cross-member with small block mounts and stands. Fits like a glove in the frame.
My question is the forward holes. There are three holes on the passenger side and 4 on the driver. Shouldn't they match on each side so the engine is moved equally forward, keeping it straight with the frame?
Do you use the forward most holes and the frame or cross-member compensates?
Thanks guys