I typically Main Tank and Stun for Ifrit and Chimera fights. Ifrit is easy - Just learn his rotation and you'll never miss a stun. Chimera can be difficult due to how random his abilities are, but if you're only auto-attacking you shouldn't ever be animation locked. Animation timers can be an issue with most of our abilities, but shield bash usually goes off rather quickly. Do you run any software to monitor or record your ping while you're playing?