Physics behind the electrical ascending aid

First of all, what power do I need to keep a paraglider in the air?
From a very simple model, we can estimate the power we need to keep us in the air (without ascending or descending).
If my paraglider has a sink rate of about 1m/s and weights 110kg (weight force: about 1100N), than I need a power P of : P = F x v to keep me in the air.
That means only about 1100W. That is independant of the power source. With an propeller and a efficiency of about 50%, we need 2200W on the propeller to keep us up. Every additional Watt would give me a lift.

Second, what power do I need to get me in the air from ground?
That is far more complicated. The moment with most power consumption is the phase when the paraglider is just behind you at the start. This is the "parachute" moment. The full canopy is open, but not above you, it's behind you and causes a tremendous drag.
The power of the paramotor needs to compensates this drag force and needs to deliver a push force of 500-800N (50-80kg) in a normal condition.
Just for a few seconds, but without this power the canopy will not rise.
As a foot starter you deliver also a lot of power to overcome this drag with your feet. In a trike configuration, the motor has to due all the work and needs even more power.

What is the best canopy?
Normally a reflex canopy is used for paramotors, because it is more stable at higher velocities. But the reflex has a drawback, it has a lower glide ratio as a standard paraglider. The glide ratio defines also the vertical sink speed at a given horizontal speed.
Just an example: the glide ratio of a reflex canopy is half the glide ratio of a normal canopy. That means roughly that the glider has double the sink speed. That means we need to double the power to maintain us in the air.
So the best choice is a standard canopy. We can't fly to fast, but the goal is to reach the next thermic, nothing else.