[CUnknown]

One option is my crazy-psycho 9 province start idea from that game a while back. It can jump-start things, giving armies a head-start on gem-generators. Of course, the gem-generators will catch up, it's not much of a head start, but it's something.

Another idea along the same lines is to greatly lower indy strength, like to 4-5. Then people will be up in each other's faces faster, making investment in gem generators more risky.

Also, given the huge gem incomes everyone will have anyway (just from the 75% sites thing), gem generators are diluted somewhat and are of less value. i.e. It's better to take a province rather than build a clam under these settings. Of course, everyone will just be doing both, but hey.