I'll try to put my own spin on this, but this is just based on aerodynamical knowledge relating to full size aircraft, so it may not be fully applicable here.
You want your center of gravity (CG) to remain exactly the same as it was as a trike, since this will determine how well the aircraft flies. But since the main gear were aft of the balance point, and the nose wheel that supported the fore portion of the plane is now gone, you need to move the main wheels forward of the CG, while maintaining the same CG as before. Depending on the Main gear to tail gear weight ratio, and the differences in moment caused by their distance from the CG, you will likely have to re-balance the aircraft by moving some of the weight backwards. Most likely by moving the battery pack further aft. The weight ratio of the two gear will be the biggest factor on how much you have to adjust it. If you have a heavy main gear and a light tail gear like my Sig, you will have to move it further, but if there isnt much difference in the mains and tail wheel, then you may not have to move it much, and in a perfect situtation, the arm of the tailgear may be able to counter the weight of the main gear. I hope I havent gone and confused the situation more.