It would be nice if the compacting upgrade had an option to keep a stack of every compacting stage available at all times.

So if you have a limited barrel III for example, it wouldn't automatically compact all your iron into blocks requiring you to uncraft them all the time.

I foresee this as as doable with 2 options:

1. An option to only compact overflow, that is items in excess of a stack.
2. The ability to uncompact items if one of the stages falls under a stack.

Maybe the uncompacting upgrade could be another upgrade to achieve this functionality, that is having a chest with both a compacting and uncompacting upgrade, and enabling the option to only compact overflow.

There's compression upgrade that does what you want, the only thing where keeping a stack could help is making sure that slots stay reserved for items to be compressed and don't get taken by other stuff making it impossible for something like ingots to go into inventory, but even that can be easily handled by memorizing slots to those items. So I have no plans of adding this functionality.