(Noob) Flood Fill "similar colors" dynamically so I don't have to ctrl-Z and redo?

[tgm1024]

Gimp 2.10.6 / Linux Mint x64 18.3 / MATE

Brief:

Can I do a flood fill with similar colors but see the results as I slide the bar (dynamically)?

TL;DR:

When I use the bucket pouring flood fill, I'm routinely using the option to fill similar colors.  But this can be a dicey proposition with most images, and if I'm not super careful, I will end up with a flood-leak all over the place.

The way I've been managing this is this:

1. Try a percentage
   
2. See it be not be right
   
3. Undo
   
4. Rinse/Lather/repeat as needed at step 1.
   

Is there a way to do this dynamically so that I can see a before shot and dynamic after shot so I can just move the slider and see the results "right away"?

THANKS!