Most aftermarket off road pedal assemblies that are similar to the M3W are in the 5:1 all the way up to 7:1. The most popular seems to be the 6:25 ratio.
But really, if the caliper is working correctly, the pad basically just about rubs the rotor. So tons of fluid volume is not needed, but pressure is. The slightly smaller diameter master will net you more pressure at the caliper, but if the pads are too far away from the rotor the extra pedal stroke to move the pads to the rotors will take away from your high harder pedal.
Now the drum rears could be at fault as they tend to be more relaxed in run mode and usually have to move a bit further to make contact with the drum. I'm not sure about the auto adjuster system in the rear drum. Some of the older domestic drum brakes would only "adjust" when you were in reverse and pressed hard on the pedal. This would trigger the ratcheting star to unthread a bit to take up the slack.
If your brakes were sufficient at the beginning and now seem to be a bit mushy, it's probably something mechanical that's happened to cause more pedal travel.
I don't know what DOT fluid is used, but if it's DOT 5, that's silicone based and it's a PITA to bleed and to ever get a hard pedal. Most bike guys with DOT 5 drain and go to DOT 4. But IF your system is the silicone based DOT 5, you would need to completely flush the lines and calipers to use the DOT 4 fluid. Also DOT 4 or DOT 3 will eat your paint aggressively so be careful of that.
This probably is not new news to you and may not help you much.
Good luck with your pedal issue.
