I'm not an expert in any way, but Beman MFX Classic 400 should be the correct spine,just buy one full length and see how it shoots, you can easily shorten a little at a time and experiment with different weight up front. when you are satisfied, order the rest. If you have access to an archery shop, you can do it there, it only takes a minute to cut it down while you wait. then shoot again, I like to have someone stand behind me to watch the arrow flight, gives me a second opinion and I can focus on form rather than trying to watch the arrow.
Rod