The y harness is easier, you just plug into your aileron channel and get servo extensions that will plug in from the y harness and reach your aileron servos. You just have to setup your servos so the ailerons move equally in opposite directions.

Most of us that fly 3D or aerobatics use a 2 aileron channel setup so we can use aileron diff, flapperons, spoilerons etc. But on a standard sport, scale or aerobatic plane a y harness is perfectly fine.

Mike

PS whatever you do be sure to secure your servo wiring connections with tape or something so they dont come unplugged and result in a crash.