add tune2fs reserved block count?

[theflyingape]

I may be missing something critical, but here's my ask:

When pishrink.sh creates a new target image filesystem for optimizing and shrinking, can it allow passing a parameter for a reserve block count, i.e., tune2fs -r $(( $BLOCKS * 1024 )) and bypass mkfs default 5% overhead?

With larger SD cards of 256G, 512G and 1T becoming more mainstream, 5% is a LOT of space that can't be immediately used for data when unpacking it onto a new target card.

For example, on a 256G card with 5% reserved, I have less 1G available to work with. I set reserved blocks to $((64 * 1024)) and now have 12G free. If I load another 10G on it afterward, then pishrink.sh -avZ, I can't restore it to a same size SD card.