IIRC the concurrent agents setting in the Agent Manager tab is how many scheduled agents can run concurrently. I do not there is a limit on the number of user-activity triggered agents running concurrently.
I think your best bet is to enable the "RUn Web Agents Concurrently" setting and rely on Java if you need to multi-tier/multi-thread your web triggered agents.
IIRC the concurrent agents setting in the Agent Manager tab is how many scheduled agents can run concurrently. I do not there is a limit on the number of user-activity triggered agents running concurrently.
I think your best bet is to enable the "RUn Web Agents Concurrently" setting and rely on Java if you need to multi-tier/multi-thread your web triggered agents.