My size will not help much-42 scandium frame no longer availabe in the Lightning but is available in the Classic. I could ride either the 42 or the 49. But look at the top tube length and seat tube angles. The 52 has a top tube length of 54 cm a seat tube angle of 74 degrees. The 55 has a top tube length of 55 cm and a set tube angle of 73 degrees. The "reach" for both bikes is the same. You may get a better fit on the 73 degree seat tube for road riding. I'm guessing your leg length will fit either seat tube length. Then the issue is whether you have too much or too little drop from the saddle to the bars. But you have head tube spacers and flipping the stem if needed to work with. I would start with the frame size and stem length Richard recommends. He will send you different size stems to work with as well as different degree of rise. Work out with Richard the cost if any of returning a bike for exchange. BTW in my opinion Wabi's are an outstanding value and Richard's custom service is excellent.