The biggest part of trenching is caused by the steep approach angle of the Yamaha suspensions. If you want to stop it from trenching, you'll want to reduce the approach angle. And yes, adding more track will increase the flotation, so reduced trenching there as well.
If you want the ultimate 144" setup, you want to get some 136" skid that is compatible with relocation (ie, ExpertX --- your stock suspension can NOT be safely relocated), and set it back 4" with a 144" track.