Maybe a little low on ammo, but with skills it is manageable. If you find yourself running out often, drop the jj for an extra 1/2 ton.
Mixing the MRM10 with the MRM20 is the same as using an MRM30, but it uses 0.5 more heat per firing, which is nothing. I do think that splitting the MRM up is a good idea to pad against crits. However, you can build this with an X180 with a ton less ammo: MRM30 _ MRM10+MRM20 _ Edit: Stack the MRM20 over the MRM10 in the loadout, and it'll stack higher in game.
MRM20 and 10 have a tighter spread than MRM30 and each missile takes more AMS damage to bring down. The difference is not as large as between the MRM40 and the 10/20, but it is there. Since the 2 launchers are stacked on top each other in a compact array you can actually benefit from this minor tightening of the spread.
