Aluminum Brazing Questions

I am making some trim using the aluminum stock sourced from the hardware section at Lowes.
I want to fix studs to the back side to mount it and am planning to use flat headed steel screws. These are small diameter screws that will hold only the trim in place, won’t need to hold much weight. I don’t want to drill through holes and have the mounting screws show.
1) Using a propane torch and aluminum brazing rod can I braze the steel screw to the aluminum strip?
If so any tips on how to do this?
2) Concerning aluminum brazing rods, I can buy a pack of 5 rods at Lowes for around five bucks. I also saw Muggy Weld aluminum brazing rods on the internet for a lot more money. Concerning aluminum brazing rods, does more money spent get me a better brazing rod?
3) I know about making sure the area to be brazed is clean and free of oxidation, is flux used for aluminum brazing and if so is the flux different from the flux used for solder?
Thanks