Not sure about 7.1 (there might a registry setting under HKLM on the WG server(s)); more recent releases of 7.2 upwards, you have the option; In TES > right click on Datasets>Event Processing>Configure>Options; there's a bunch of settings (have attached screen dump reference). Would recommend you seek advice from HP in the first instance.
You could just perform a Word/Text Reindex (Based on your attachment, the Word index Queue is extremely high which implies a bulk data migration to TRIM has occurred).
In my view the best performance was to have the interval set to a small value (so the event processor responds quickly) and the batch size to be the amount the server can typically process in that interval when fully loaded.
So some trial and error is required as it will depend on you hardware, sql server response etc.
For the setup i was using at the time I have 7.1 going, I had the interval down quite small (5000 ms) and a batch size of 200.