So thats +800ft for terrain, +500ft for obstacle
The legal minimum for IFR flight being 1000ft above the highest point within 5 miles of track and for VFR I was taught to use 1000ft within 10 miles as a safety altitude. neutron
The MSA for a leg is calculated by looking at the terrain and obstructions 4nm either side of the leg, with 1000ft clearance for obstructions and 800ft clearance for terrain. These options have been exposed ready for the forthcoming 1.4 version so you'll be able to change them then.