Butt coupler / joint vs continious run for resistance loss

So, any super nerds out there that can help - I'm using Amphenol's G2 series 300 connectors for my 2/0 cable.

All these high-end connectors require multiple tooling and time to assemble - man tear ($$$) are at the feet of stupid mistakes like forgetting to mount a ring before you did this-or-that and now it can't be undone or reversed or blah blah blah (<cursing and being forced to order a new $100++ connector).

So, the question I have is, would a pig-tail design reduce the resistant of the overall run - point A Connector to point B connector vs point A Connector to butt joint to point B connector.

I can build a G2 connector in a controlled environment (my dinning room) attached to say a 24" length of 2/0 cable then make my run in the vehicle, join the butt to butt end to the pig-tail and Bob's you Uncle.

The question is, how much do I loose in resistance with a butt joint?

Obviously, I would use an industrial, hex crimped, tinned, copper connector then a double wall, adhesive heat shrink over it for both strength and water proofing.

Thoughts?

- Patrick