should I run Gas or electric to run my 70'' extra

which one is better to start to learn I have heard that Imac the bigger the plane more chances are you will win. I am just starting to get into Imac or pattern but dont know which one to go to leaning more to Imac i have a EDGE 540 47" wing that I will be flying in November what would you say is better or are they the same?

which one is better a deans or a ec3's I want to switch to ec3 but not sure

I am building my first IMac plane. I have been thinking about doing a pull pull system on it rather than a push pull. I am just going to do the basic pattern this year and build a bigger plane for next year. My plane I am building is a Edge 540 47 in wing with a 3548 800kv Turnigy don't know if I want to run 4s or 2 3s together? I am asking what is the big difference from a pull pull than to a push pull system which one is better for say