If you only add 17 to 20% in ecu editor, you will blow up on a 60 shot.
In ECU editor, the percent you increase is pretty close to the percent power increase. So for example If recently added a 50 shot to a 210 HP base motor and ended up at around 23% increase to get me to 12.2:1. 260/210 is a 23% increase, so the calculation is a safe conservative starting point that will put you rich to start with. I don't know what your baseline corrected power is but assuming corrected HP baseline of 190 with a 60 shot : 250/190 is a 31% in ECU editor to your MS1 map over your baseline MS0 map in ECU editor. Remember you will need to check and adjust. Depending on fuel you may wish to pull 2 timing, but C16 or even C12 you can probably leave at stock setting since timing is pretty conservative on these things from the factory.
Just to make sure we are using the same definition for percent, if you have an ECU value of 255 and you wish to add 30%, the new value is 1.3*255 = 331. Not 255 + 30 = 285.
Hope this helps.
Tom P. Boston.