PredBat - Export only during Savings Sessions

I have been running PredBat in Charge Only mode as we only have one 5.12kWh battery and it didn't generally seem like it was worth cycling the battery for a very marginal gain and then potentially running out and having to import at peak or day rate.
There is a Saving Session for Octopus today though and the grid actively wants our help, and PredBat would definitely be the easiest way to manage that so we don't export at maximum rate and run out before the evening Cosy slot.
As far as I know there is no Saving Session only mode for Exports, but could we effectively simulate it with predbat_metric_min_improvement_export?
If I set it to something like 5p then it presumably would allow some summer forced export when the energy was free and came from solar, as well participation in Saving Sessions in the hour of need.
If I want to be conservative I could also set predbat_best_soc_keep to something like 0.5 so that PredBat doesn't plan for a completely empty battery at the start of the charging slot.
I presume I would need to switch to Expert mode and enable control discharge.

One way would be to have an automation so that when the next half hour is a saving session (cant remember what this looks like in the plan but maybe if the export rate jumps over 12p) then switch mode and then when the rate drops back to 12p switch back to charge only.
I don't do it quite like this but I have timed changing of the mode at 17:00 (switch to charge/discharge) and then at 05:30 (switch to charge only) so that mine doesnt discharge during the early morning or in the day.
I'm not in a saving session region today so can't see what it looks like I'm afraid.

pwdst you can set a manual export rate override in apps_yaml for the savings time period this will then export if you have battery soc. in the past export counted towards savings.

All good ideas folks, thanks

There isn’t a saving session only export option, I think the idea of changing mode if a session is coming up is probably the easiest/safest. Use the saving session calendar to trigger the automation.

Be careful with predbat_metric_min_improvement_export as the improvement amount is the amount for the whole 30 minute session, so you’ll probably get export in far more sessions than you’d like. Would need to set it to a higher value but TBH I am not convinced those metric_min_improvements work properly, I’ve seen examples of behaviour that shouldn’t happen, but never really looked into it in detail as its pretty much edge case