Need help in setting Arducopter for the first time please

Hi all,
Just setting up arducopter on omnibusF7V2 board.Most of it’s done and i was able to hover in stabilize and position hold mode.Really liked how my home built balsa H-frame quad flew!!

Now i got few questions:
1)I couldn’t change flight mode channel.I tried to change the flightmode channel in parameters from default 5 to 7 but on mission planner’s flight mode page,it was still defaulted to ch5 and was not turning the flight modes.I had to go back to ch5

2)After turning off my Transmitter,quad enters failsafe properly but on mission planner’s radio calibration page,it still displays the last channel values (values while switching off the Tx) instead of 0 pwm values.I am using Frsky X4R Sbus reciever.I even pulled Sbus wire from the receiver but mission planner kept on showing the last values.Is it normal?

3)Is there any way to control the min RTL activation distance from home?Lets say i am flying indoors within 4-5 meters from the arming location and i loose my RC signal,I think quad would shoot up to the set altitude for RTL and will crash into the ceiling.It should not enter RTL if its too close to the launching location.

Thanks in advance.

1 ) Did you try a reboot - set the parameter and write then reboot ? Just a thought…

3 ) RTL cone slope is what you’re looking for
So a slope of 1 equals a 45degree cone, as wide as it is high.
Also check
Alternately, just set the RTL height to suit your flying location; for example indoor might be 5m, outdoor might be 40m