Gubbins, it is preload that you require to bunny hop, not rebound! You preload the forks using your arms/body as you initiate the movement, and rebound has no relevance, other than from your own pulling back of the bars.
Can you imagine having to stop to adjust rebound settings every time that you want to go over an obstacle, then stopping and adjusting the rebound again because it is then set too harshly/softly and incorrectly for riding there after and between.
You should also find that the bikes weight doesn't really make a significant difference, and it simply comes down to good technique and practice. This is especially true, given that you have an electric motor to assist with the initial lift. Riding through the plantations that I do, with many fallen trees, or wood that has just been left to rot, bunny hopping forms a major part of the riding. You will get it in the end.
I'll try and find you a decent clip demonstrating the technique a little later.
edit.. That didn't take long to find one, and as usual Seth makes it looks second nature. Note that the clip continues after the 2.03 point. I would add to Seth's clip by saying that a certain amount of speed is also of great help, as is practicing over curbs in a car park.
Ref your front forks, if they are working for you as they are, why mess with them? If you aren't happy with them, then use the online 'guide' by Fox. You can't take advice when the person giving it doesn't know your weight, riding conditions, terrain, or speed. If things still aren't working out for you, just take a shock pump out on a ride and play with the settings. Make a note of the settings prior to doing so though, as you will always then have a reference to return to.