Ah, that makes sense.

Now, back to the drawing board...

Also, out of curiosity, can you cast metamagic-altered spells using a silver generator? Because if so, I've got a method that causes the amount of energy that thing produces to increase by at least 1 ebb with each pass (maximized CL 8 Fireball produces 8 ebbs, and takes 7 to produce. You could have a pair of generators, each bleeding off the necessary amount of ebbs...)

So, it would go: maximized CL 10 Fireball into an Ice In generator, producing 10 ebbs; 7 of those would be used to produce another fireball, which is then cast into the silver net, producing 10 more ebbs...

Get a place to store the 3 extra ebbs so that you can feed them back in (get 3 running in tandem, taking turns using the extra 3 ebbs to produce another fireball; the amount of ebbs produced by the set increases by 3 each round...)