When you are trying to knock out a rock golem, have a paracer with some sort of cannon on the back of it put that futher back away from the rock elemental and start to place pillars in between you and the rock elemental. Get its attention and try to run avoid its attacks and get on the turret while it's attacking the pillars and fire away at its head!!
It's a bit silly that kibble tames it a lot better than rocks or sulfur because even in the dossier it says that it lives off of absorbing nearby rocks and minerals. So mabey they should make it so you have to feed them a rare mineral like obsidian what if they made it so you could tame one fast and with high effectiveness by giving one a few hundred or few thousand obsidian . or what if there kibble was made out of a combination of ores and minerals .