For a 700' run, I would not use any main feed line smaller than 1" black poly....2" would be better! Small diameter line may SEEM cheaper, till you are replacing pumps every year or two due to excessive heat and head pressure from friction. Are you planning to use air stone diffusers? The need regular monthly cleaning, so nix the idea of anything other than self-weighted air tubing. Bury some Poly tubing below your frost line if at all possible, and install a buried valve box to balance diffuser stations. In all honesty, if you are not mechanically inclined, you will be far happier and maybe save money in the long run to get a professional system installed for you.....