I have ordered a servo and elevation recoil unit to use and just tested recoil using another servo I had using the output for gun fire.
It works each time with recoil set on cannon fire which is great. (Have not tried setting to mechanical
trigger or see need to?)
I assume what you mean to say is that you have left the "Trigger with Cannon" checkbox checked, so that when you active the cannon fire function, the recoil action occurs. That is the way most people will want to do it, the other options are for unusual setups.
One thing though and not a big deal..upon turning power on... Servo does some fast movements then upon triggering cannon does the proper fast/slow recoil return movement. I have not adjusted end points or anything yet.
Yes, I think this is not a problem. The behavior of some output can be erratic on boot depending on the position of your servo, the status of your receiver, etc... As long as it ends up in the correct position when boot is complete, and as long as it works when you trigger the function from your transmitter, then I think everything is fine.