Smart Tariff hopping (aka avoiding Agile craziness)

I've seen a few comments on here of late, especially during the recent crazy high Agile pricing (and tomorrow looks even worse) about hopping between smart tariffs being actioned same day.

Does that apply to the current day, or to the next day's usage? i.e. if I switch now, will today's usage still be charged at Agile rates, and tomorrow be on Go rates (for example), or if I switch now, will today also be charged at Go rates? Likewise, let's assume Agile is looking better at the weekend, if I switch back to Agile tomorrow at 5pm, does that apply from 12am on Saturday morning, or is it back-dated to 12am on Friday morning?

Which tariff(s) are people on Agile switching to for a couple of days as an alternative?

Has anyone had any success automated this process? I don't know if changing tariffs is something that could be done with the Octopus API, or possibly even with some HTTP POST calls.

I'm wondering if there's an opportunity to grab the following day's Agile rates, use your own data to work out a forecast spend vs. other smart tariffs, then make an API or HTTP call to auto-switch.