EG brake master cylinder / booster upgrade question

Just upgraded the front brakes on an EG Si to some 262mm EG6 brakes, however yet to upgrade the master cylinder / booster (much needed).

Anyway, I've been advised to try to track down a master cylinder with the same mounting bolt pattern (top left and bottom right) so I don't actually have to change out the booster, however it's looking like it could be a stretch to track down a 15/16" or 1" MC in the same bolt pattern.

I've looked at the MC / boosters on an EK and a DC2R and noted the MC bolt pattern is horizontal rather than diagonal like on the EG. I know the EG MC mounts to the same bolts used to mount the booster to the firewall, so just wondering if this is the case with the DC2 and EK? Or is there a separate set of bolts from the booster for the MC to bolt to?
I guess the main point of the question is whether EG's, EK's, DC2's or even Preludes all have the same firewall mounting pattern for the booster, regardless of MC mount? That way, regardless of what I get the booster and MC from it will bolt up to the EG.

Thanks and sorry for the long windedness

i used a dc4 15/16" MC and booster on my eg2 with no hassle, so yeah for EG/DC being the same.
Never really looked at EK.
15/16" MC is an straight fit just note on abs MCs they have 1 bigger hardline fitting to the prop valve. 1" was only on abs cars so needs bending and re flaring of a hardline to fit the larger fitting.
Booster from 1"MC only fit the 1", 15/16" below should be swapable.
If your not running abs just look for something 15/16" without abs.

cheers. yeah I think I'm just going to get a DC4 mc and booster and change out the lot