A simple A of A indicator is the stick. If you paint a line on the fus wall at the correct place, then if the stick is aft of that you have exceeded the critical A of A and the wing will stall regardles of speed, so the message is, always be aware of the stick position. Suggest you hire an aerobatic a/c with a good instructor for an hour and play test pilot and explore some of the corners of the envelope. Have fun!