The maximum working force on rigging can be estimated under the assumption that the boat capsizes with all crew hiked fully.
This assumption gives you the maximum heeling force before the boat goes over. If you assume that not more than this force can act at the tip of the boom, you can figure out the maximum loads for your sheeting arrangement.
In usual operation, you can adjust the main in all conditions, meaning that your maximum "pull" on the sheet is strong enough that, with the 3:1 purchase, it can overcome the wind force on the sail. That estimate will give you another, smaller number.
Finally, an uncontrolled gybe will put shock loads on your rigging which are not covered by these two estimates. If your boom is bent to port, rather than up, chances are a crash gybe in high winds was arrested by the mainsheet. Looks like it didn't tear out your blocks, so that would argue that they are strong enough.
However, we don't know the actual history, including whether someone put the boom on the lawn (or other soft ground) and accidentally drove over it.
If worried about center boom loads you could always switch to end-boom sheeting.