I wish they had a cannon version that let you build RLs one rocket at a time, and could fire one at a time -- for bit of longevity, or full strike at once if needed.
Make it where smaller salvos have longer ranges, while larger salvos have more fratricide? Similar to how the different RL have decreasing ranges based on their size? But then you'd have to re-cost and re-mass them so they have cost and mass proportional to their salvo size. One idea might be using Fractional Accounting, and make them a quarter ton per 5 rockets. This leaves the RL/10 as its current mass, and turns the RL/15 and RL/20 into .75 and 1 ton each.
You then have to go with costs. LRMs are 30,000 C-Bills for 120 missiles, or 250 per missile. Rockets are lower capability, so maybe 200 per rocket, plus 25 C-Bills per launch rail. That would be 225 C-Bills per rocket, or 1125 per 5-pack. So RL/10 is 2250 C-Bills, RL/15 is 3375 C-Bills, and RL/20 is 4500 C-Bills.
You'd have to add a rule where all rockets fired from a unit are put into a single salvo to determine range and fratricide. So if you mount 10 RL/10, and fire all of them, it is treated as RL/100 for range adjustment, and after figuring the range adjustment you'd remove a number of rockets proportional to the 100 rockets fired. Personally I'd like to use (salvo size)
2, times a multiplier (i.e. 1%), fractions rounded down
Assuming the multiplier is 1%, that means if you fire the equivalent of RL/100, you multiply 100 times 100 giving you 10,000. You multiply 10,000 by 1%, giving you 100. So the entire salvo essentially self-fratricides during launch (wasting 22,500 C-Bills and 5 tons). A RL/10 will only lose 1 rocket due to self-fratricide, RL/15 will lose 2, while RL/20 will lose 4.
This makes them into a very cheap weapon and better used on 'technical' vehicles. Technicals have fewer launchers, so the rate of fratricide is lower. Given the cheap cost of RL, they can be spammed easily, but their lower accuracy should result in fewer hits.