Tandem wings don't interfere with each other if they're separated by more than two chords longitudanaly and more than one chord vertically.

The front wing is close to the ground, and the rear wing is up on a pylon. The frong wing will gain lift from ground effect, to assist getting off the ground in less than 200 ft. The aft wing has flaps, to gain added lift at low speeds.

With more wing area, an airfoil can be chosen with a better lift-drag ratio, and still lift more weight than an airplane with less wing area and a more drag because of its high-lift airfoil. Fringe benefits, you might say. More lift and less drag, too.

Here's a link to a drawing of my canard, which is designed for a distance competition. Not the same as weight lifting, of course, although ROG with 1/2 gallon of fuel is required. That's over three pounds, plus the weight of the airplane.

For weight lifting, I would make the "canard" almost as big as the main wing, and set it at the bottom of the fuselage. The landing gear would be much shorter (two sprung axles with skate wheels for the mains, and a short steerable nose wheel). This puts the forward wing close enough to the pavement for good ground effect.

Instead of the pusher, I would place the engine on the front of the pylon, above the fuselage. This will put air over the main wing, for lift to match the canard in ground effect.

"Flaps" on both wings work as elevator on the front wing and flaps on the aft wing. Steering is by spoilers on the outer main wing panels, which have dihedral.

Here's the plan view:

http://www.rcuniverse.com/gallery/sh...t=1&thecat=500

And here's the profile:

http://www.rcuniverse.com/gallery/sh...sort=1&thecat=