Spoileron is an erroneous term. Spoilers deploy just aft of the center of lift disrupting lift and creating a rapid descent without adding airspeed. On a symmetrical airfoil all you are doing is creating negative lift and negative incidence, which as stated earlier will just destabilize the A/C. If you want to shorten your landing add just a little flaperon, and learn short field landing techniques. Bring the plane in over the trees as if you are going to touch down at the end of the tree line. you should time it so that the point you would flare is right were you need to start your descent. As you cross the edge of the trees drop the nose a little, this will cause it to drop towards the runway, you will pick up just enough speed to level out and flare. If done correctly you will not balloon or float, but just flare to a nice slow (for that plane) landing. Your setup and approach will do more for your landing then any amount of mixing.


*Edited for spelling*