brake master cylinder alternative and sizing

[Hoghead]

Beetle with 996/Boxter S callipers Front (2 x 36mm) + (2 x 40mm) and Rear (2 x 30) + (2 x 28mm)
996 rotors front and 944 rotors rear

I bought a 944 (20+24mm stepped bore) master cylinder for this project and now find that I cannot buy a rebuild kit. As you might imagine a new Porsche MC is prohibitivly expensive

Several BMW and Mercedes W123 MC - look very similar to the 944. The Merc is single bore 23.8mm. There are several BMW sizes in both straight (21-26) and stepped 26/20, 21/19, 22.2/17.4 bore
There well may be other sizes as I am only as smart as my internet connection
If so that might be a good alternative for those with the unobtanium 944 MC

I am now thinking that the combination of rotor OD and piston size on the front is too big in comparison to the rears, but rotor width prohibits swapping them around. I have too much money into this now to change as I am in Thailand and importing all this was a bit costly.
Any thoughts on a stepped MC VS single bore to compensate?
I have a proportioning valve

Compounding my problem is that I am RHD, and the 944 lines exit on the L right into the tunnel hump, requiring a bit of clearancing that I would rather avoid if posible.
Any suggestions for a tandem output MC that fits the stock Napoleon hat holes? One with the output lines on the R would be nice but I do have a hammer

I see that some use the stock 19mm MC with these callipers, but would a 22mm MC give me a better calliper to MC bore ratio??

[flat]

https://socalautoparts.com/product/m...l-disc-brakes/

[Hoghead]

Originally Posted by flat

https://socalautoparts.com/product/m...l-disc-brakes/

Thanks Lanner
R and L hand is nice, as is 4 outputs per hand + the brake switch

So a 20.6mm single bore
Install the proportioning valve on the front to adjust the bias, or leave it as is?

[flat]

As is