Fortunately, most of the charecters are already at the point where it would be smart to switch to a training plan that does not require Noburi to provide chakra for shadow clones.
@Paperclipped designed each of his plans to come with a "No-Buri" variant where the charecter slowly raises their CR alongside their clone usage. I have been arguing for Hazō to take this approach on its own merits (higher chakra reserves being a good thing for a lot of reasons), but now that we have major OPSEC concerns I feel it is a no brainer.
This DOES NOT slow down FOOMing more than a very small amount. For Hazō, it would take him 2 years 5 months to get to the point where he is a kage-level sealer that can survive and escape from an ambush by a hostile jōnin instead of 2 years and 3 months. Yes, it only adds two months. For Kei, it's even less of an impact. It would take her 3 years to reach the her fourth detour instead of 2 years 11 months. Akane likewise is barely affected, taking 2 years to become a terrifying combat monster instead of 1 year 11 months.
I strongly encourage everyone to take a look at the specifics in the spreadsheets linked below. Paper did a really good job with them and they are totally understandable even to people with very minimal spreadsheet experience such as myself. I pulled these numbers straight from there.
Resolve Grinding (Hazō)
Resolve Grinding (Akane)
Resolve Grinding (Kei)
The specific paths I looked at were the
Akane(with Buffs)/Akane(Buffs + No-Buri), Kei(with Buffs)/Kei(Buffs + No-Buri), and Hazō(Survivable Sealmaster)/Hazō(Survivable Sealmaster + No-Buri), as they were the ones I considered to be our best paths forward.
TL;DR We already have a great way to drastically reduce Hazō, Kei, and Akane's chakra consumption for FOOM training by slowly raising their CR as they increase their SC usage. It barely slows down FOOM and comes with the added benefit of giving everyone higher chakra reserves (very nice to have in combat and required to unlock goodies such as Sage Mode and possibly jōnin auras).