Oh man...so I am at the limit of my knowledge with this. But, from what was communicated to me by other suspension folks is that the spring weight should roughly be the same regardless of what cartridge is in there. The oil primarily impacts the rebound/compression damping, and only serves to cool the springs. The cartridges, only control the resistance the bike experiences on compression and rebound. The cartridges that can fit in these fork tubes vary very little. The springs are what "hold's up the bike" Thus, while springs may slightly differ in diameter & number of coils, their ultimate spring weight will roughly be the same. Someone way in if I'm wrong...because I'm at the end of my knowledge with this statement.