You should gives us more information (what is the spawn rate, what is the max ammount of diamond that can sit on the genrator, how expencie would it be to upgrade it) and i think that Level 3 is a high enough generator for diamond, and if you think that it is too slow then you can collect at mid or at a Island where the team elimated from
Diamond is the best you can get in eggwars.. spawning diamonds in like 2 sec is too fast it will makes it no fun anymore