Might it be possible to have a setting that disables the inserting of wood as fuel when using Shift C?
Or perhaps, since you already have a setting for "replacing wood with coal" using the drag method, could we also extend this to shift C? Reason being Shift C tends to dump wood into machines as fuel when you probably don't want to use wood as fuel. Coming back with coal in hand and using Shift C does not replace the wood with coal.

Also, I find it strange that when you have both wood and coal in the inventory, Shift C will choose to insert wood as fuel RATHER than coal. Could we fix that?

[edit]
While we're at it, could we please have CTRL-C able to insert other types of fuel? Just noticed that Processed Fuel, from the AAI mod, doesn't go in.

You can customize shift+c with the logistic slots. Check the mod page for more info.

To distribute other fuels add them to the logistic slots with the amount you want to keep in your inv (anything above the minimum value gets distributed). To exclude wood, add it with the minimum amount = 0 and maximum amount = infinite.

Okay that's very cool. Thanks!