How much Tylose should I add to make fondant panels? I want them stiff so they can stand alone one the sides of the cake but still be soft enough to cut. Thanks!

IF you have some time for them to dry you don't even really need tylose powder. Look at my wood grain cake. IT had a door that opened an closed on the side of the cake. The was made with straight fondant. It dried for 5 days. I dried it on the side of the cake pan I was going to bake with so it got the exact curve of the cake.

I actually only have a couple days until the cake is due

You can always do 50/50 fondant & gumpaste and it will firm up pretty well. I haven't used tylose yet.

I use 1/2 tsp tylose/CMC for each 250g of fondant. But I use this mostly for modelling and letters/decorations for cakes. It dries pretty hard. For the panels you would be rolling it a bit thicker, and it would be attached to buttercream/ganache, so it shouldn't harden so much that you couldn't get a knife through it to cut it.

Have you thought about using chocolate melts?

how about modeling chocolate? or a fondant/modeling chocolate mix?

how about modeling chocolate? or a fondant/modeling chocolate mix?