It really depends on your machine. I would use a 3 flute, 1/2'' aluminum rougher to remove as much material as possible. Use an adaptive clearing cutting strategy, if your machine will take it, DOC should be about 3/4'' for the roughing passes.
Do not use a down cut bit, you need to clear the chips. Flood coolant would be the best, but a good spray mist would work.
Most of the load on the tool is radial, not axial.
Pre-drill where the 0.093 radii will be to reduce the cutting load on the 3/16 endmill in the corners. If possible, make the radii at least 0.100 to reduce the contact area of the 3/16 endmill as it cuts into the corners. 1.5'' is a large DOC for a 3/16 endmill, I would use an endmill with a relieved shank and about 1/4 inch of cutting length, then spiral down for the finish passes.