That's a great idea! I did take one of the mantid's tarsus for that purpose, as you can see in the picture it has a very under-developed pulvillus (sticky pad). In the non-Empusidae families of mantids (especially the Rhombodera genus in my observation), you see more pronounced pulvilli for climbing smooth surfaces.
In my opinion, the Empusidae lost the need for pulvilli over time and species that put them to use (those spp clinging to leaves) developed larger ones.
I believe that bark, sticks, and any time of stemmed organic matter will be the best thing for Idolomantis. They don't live on nets in the wild, so I don't know why people would put such a notoriously difficult species in an unnatural environment.
I do have the skin from the Idolo, I'll give it a try this week in the SEM!