You may want to rig up something that extends the sides of the cross and compound slides out to where a more open and thus more easily set protractor scale is incorporated. This likely means you'll need to exercise your tool making ability.
For a couple of regularly used angles you may want to fabricate up a set of angle setting guages. These would be a precisely made triangle with a fence along one side that when pushed up tight to the cross slide side can then be used to set the angle of the compound. The three obvious angles for these quickset guages would be 30, 45 and 60 degrees with a 90 angle being set using a set square.
