If the idea of using software to help you attack turns you off, you can do every thing the program does with a manual wheel and 2 charts.
wheel:
lead angle (zero gyro) chart for 90 degree shots:
https://docs.google.com/spreadsheets...it?usp=sharing
90 degree intercept ranges at various bearings:
https://docs.google.com/spreadsheets...it?usp=sharing
^ That last link takes the place of the red range wheel seen in the software (right side of window). I didn't get a chance to showcase that functionality.
ex. If the target is at 3500m at bearing 315, you are 2500m away from where it will be when it is at 000 (provided you are on a 90 degree intercept). As seen in this quick video: