Very lost: GH4, Isco Ultra Star 2x using 4:3 in FCPX

[Turnwolf]

Hello,

I've been following this page for a couple months now. I recently bought a ISCO Ultra Star 2x adapter to use with my GH4 in 4:3 Photo mode and have been shooting some test footage. When I bring the footage into FCPX 10.3.3, scaling the footage is driving me crazy. 

What project resolution do I need to use in order to get a "normal" looking master file with the cinema scope look? Also, what scaling do I need to do to achieve the 2.40 cinemascope ratio. I am just confused on the math for aspect ratios, desqueeze % and project resolutions. It is much easier in premiere but I would like to use fcpx as it runs better on my macbook pro.

Can anyone here help me set up my 2x Isco with my FCPX workstation so that I can be more efficient in creating films?

Thanks!