If you want to swap the cam to the lunati then get the springs that match the cam instead of guessing. I will likely guess the springs on your engine as the most common and popular springs, the remakes of the GM "Z28" springs and I have seen many companies remake these and give them different lift limits. Most the time they are used because they are common and cheap.
Since your using a flat tappet cam, whichever cam you use, make sure you get the correct oil to break in the cam with, if you use basic off the shelf motor oil the cam will go flat due to lack of anti wear additives. Valvoline makes a "racing" motor oil as they call it that they claim still has the needed additives in it. However I am sure other guys on this site can tell you what to use better than I can as I don`t keep up with flat tappet cams ever since I started using roller cams.