Im looking for a center columb for this tripod, hopefully used to keep costs down. This tripod does not have a round columb, but has 3 flat sides with rounded edges on the rest of it. What center columbs from what tripods can I use for the 3021 Pro? There is a columb under part number: Manfrotto Compact Advanced - MKCOMPACTADV-BK for sale. Will this work? Or what about this part: Manfrotto R1035,21L1 used on the BeFree units?