Injector Questions

I wouldn't adjust the fuel pressure to correct for the injector size.
Take a look at your ecu which is located behind the passenger side kickpanel, and see which one you have.
There will be a 3-4 digit designator in larger bold font on the sticker.

See if that 3-4 digit code is in this list...specifically any of the "GU**" folders...
OpenDNS

If it is, then you should be able to run a Moates QH to allow you to change the injector settings.

If you are changing the engine enough to need 24's, then you probably need a tune anyway....
The X3Z isn't the only way to get to 24's, but it is an option.
An A9L, calibrated MAF would work as well.
So would an A9L and custom tune.... regardless of what MAF is used...