I can -highly- recommend two Eternities and two Electrum Hourglasses. RT's are great, but those two permanents in tandem kill a -lot- of decks in Bronze and Silver alone. I'd probably even run Golden Hourglasses despite the high quanta strain, though I'd find a way to pack 13 factories. You can toy with 4 Dunes, 4 CP's, 13 factories and replacing a few RT's with the aforementioned combo.
More RT's -might- be better against Silver due to more PC. An alternative to Hourglass is Golden Nymph to reduce PC weakness.