Not familiar with the round or powder in question, so I cant comment there. I will say that a certian amount of powder compression is OK, as long as it is not to the extent it forces the bullet back forward in the case under use. When using a charge that nearly fills the case, in the past I have used a brass drop tube 16 inches long ( a common trick used by black powder shooters) It allows powder to more fully settle in the case, and you would be amazed at the increased seating depth it can give you.
Larry