For that loaf I used cornflour, Robin Hood GF Flour, and coconut flour so tried five tablespoons.
It went well.
The next day I tried out the new pan swapping the cornflour for almond flour. It is very good. It wasn't quite as dry a dough as the first, but still worked really well.
As you can see it grew a bit and drooped over a pan edge.
I don't care.
I have a proper French bread pan and for it I am grateful.
The photo is of that very first batch of French bread from the new pan.