Refocusing after removing 0.7 reducer, C11 Edge HD

[AstroAndy]

Hello Folks

I'm wondering about a Focus question.
This concerns the C11 Edge HD.

If, eg., I am at perfect focus with a 0.7 reducer, and I take the reducer out, I assume I'd have to refocus out (in this type of SCT it means moving the primary mirror further away from the initial focus point, ie. lengthening the distance, as a reducer converges the light beam more more than native focal length.
Is my assumption correct?

Is there a approximate rule as to refocus distance (eg. say I have an EAF at position 1000, with reducer, refocus has to be at approximately position 1,250)?
Celestron says, once the required back focus of 146.05mm is reached, this works the same w/ and w/out reducer.

Additionally, how does a Barlow affect this equation. Barlow lens a bit before back focus, and cam. a bit after?
I can't use daytime focus, because Atik cams. kick in at 0.02 lowest exposure settings.

Regards

Andy