Like understanding your customer, the more you know your sponsor the easier it will be to have effective communications with them.
Work out how much information they require and if necessary have a conversation openly on when they want you to advise them, what they need in reports, how often, etc.
I would always push to lower the threshold a tad, as it’s better to have raised an issue that gets quickly resolved, than hold-back on a critical problem. After all the Sponsor is the ultimate stakeholder and should have the greatest to gain/lose from the outcome of the project.
In terms of Project Control Processes, I’ve come to consider Risks and Issues as intrinsically linked, despite that many sources and courses teach these seperately.
Here’s the logic: An Issue is a Risk with a 100% likelyhood.
Issues are problems that need to be managed, in the same way as a risk once a trigger point has been reached.
The procedures for distinct risk registers and issue logs, means that Project managers can at best incur greater administration or at worst they can lose the holistic view that a combined view would give.
Ask yourself how many status meetings have you been to where the majority of the session is spent fire-fighting the issues and zipping through the risk log right at the end – or worst still, suggesting that be looked-at at the next meeting.
If the scoring system were adequately calculated it could be that some HUGE risks should merit higher attention than minor issues and should in truth be prioritised higher up any single list.