good master cylinder for single 4 pot front brembo

[mtiberio]

I have a single old style (40mm mounting lugs) brembo caliper on the front of my EldoVert. I believe it has 2 30mm pistons and 2 34mm pistons. The feel I get from my current m/c which I believe is a 13mm is too wooden. What do folks recommend, and what is a good source used or new?

[wrbix]

Guzziology has a nice discussion and table (as I recall) of Master to Slave ratios and associated part numbers

[Orange Guzzi]

There is another source for the ratio chart.  Vintage Brakes.com

My Guzziology does not have a ratio chart. 

Wooden=too big of a piston
squishy=too small of a piston

[mtiberio]

thanks. looking for piston diameter recommenations.