I always used a 3/4" master cylinder for my Cobra and customers' Cobras.
If the pressure plate pedal pressure has changed recently, then you may want to look at a problem with the hydraulics or the pressure plate itself.
If you just want a different feel, then you can probably change to a McLeod clutch kit with a diaphragm pressure plate and ditch some pedal pressure. However, it will take some readjustment of your HTOB because the finger height will be different.