One of the great advantages of Revs is that you can fly shoulder-to-shoulder with others. That adds an entirely new dimension to kite flying. But, it's best if all parties are flying on the same length lines. 120 is a standard line length for team flying. Check around with other Rev fliers in your area and see what they use for the intermediate line lengths ... 75' to 90' being the most common. The IKE club members have settled on 80' lines as their intermediate length ... Kite Party requires 75' lines ... I think the Brits use 90' lines. Very little team flying is done on the shorter (50' to 60') lines, but some dual flying happens, so ask the locals about that length also. The 20' to 30' lengths are almost exclusively used for individual flying in the lighter winds, so no problems with what ever you choose.
With the winds you're talking about, 90# line will do you well for all lengths. Some others might recommend 50# for the 30' foot line sets. Don't even think about following the power kite tradition of using lighter lines for the bottom pair ... the disadvantages far out weight any advantages!!
If you want to stretch your dollars on lines, you might investigate making your own line sets. There are several good threads here on how to do that. If you can tie your shoe laces correctly, you can probably make line sets. Plus, you'll eventually have to learn to equalize the lengths and that's the hardest part about making line sets. Buy good materials ... Laser Pro would be my suggestion.
Cheers and welcome to the dark side,
- Scott_of_melnsct likes this