PLEASE DO NOT DISMANTLE THE SETUP !
Actually we tried looking for a level-3 or a smaller mixer, but we didn't find them at that moment. That's why we kept the level-7 mixer for the coarse path.
As you pointed out we can try an RF amplifier for it.
Using 2 dBm for a Level 7 mixer is so bogus, that I will dismantle this as soon as I come over.