Neither,
You can use the axle as is with a centered engine and transmission. The slight offset will not be an issue at all so long as pinion and transmission shafts are still parallel, which they will be unless you goof up installing springs or engine.

We have a tech tip with resources on calculating, installing, and evaluating driveline angles and such.
https://www.stovebolt.com/techtips/driveline/setup/index.html

If you get into the PDF's you can read about driveline setups just like you're about to do and given your measurements can satisfy yourself it'll be OK.

Those manuals and the basic rules in the tech tip will also help you set your pinion angle, which you'll need to do considering you're swapping axles and possibly engine.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-