I recently acquired one of these for free from a friend. So far on the net all I have found, is to adjust RV4 for modulation, and then do L10, L11 and L12....I found 2 of these towers filled with wax. Any idea what these wax filled towers are? Also...the final in this radio is a C2078. Would I gain anything to change out the final to something different? If so, what? Thanks in advance.