This is what I've been running on my Loyalty R68. I don't like the idea of XL's on Urbanmechs, but I'm going to try an XL with MRM30 and ERSL's for a little while, but this less offensive and more defensive build has worked for me for a while: _
With MRM10 having a shorter "duration" to release all missiles compared to the bigger brothers, it could be worth it despite the higher heat. This is my take with an XL engine: very high cooling, 3xJJs for pop-tarting and flank baddies _