Is there any reason you couldn't use the throttle channel/curve for the ESC's instead of the pitch channel?
I am not sure if you are talking about my project... But you do not really need a throttle lock. A 3-stages switch (channel 5) disables or enables the pitch channel (in the software of the tricopter. Like this, it is very unlikely that the motors start turning without you wanting them to. The advantage is that you don't need to program anything in your TX. Just select an aircraft mode and that's it. All settings are selscted inside my GUI.