Hey I agree with you that the P4 motor should be more powerful, I seen a video in youtube P3 lifting 2 lbs without any problem, But I did this test on my P4 in the field by hooking 500grams bottle and let it hover
Regular flight time with my battery without payload I get 23 minutes
With 500 gram payload and Hover at one place gives me 11 Minutes 38 seconds landed at 10% battery
About dropping and controlling by the remote I seen in youtube some attach additional receiver and Separate tx, And as you said by tilting down the came does the trick
If you look in my WIP box I'm not using extra receivers
View attachment 55246
I have a Slot for 2x Circuit Board, Place for battery, Servo & a tiny sensor that goes all the way to front LED and stick it there with a tape
You trigger the mechanism using DJI go app by turning on the front LED light, easy way in DJI go app assign the C1/C2 switch to turn LED on/off
btw I redesigned the final version of the Payload holder and its much smaller than the one in the PIC