Attaching wood to glass?
Two things to consider: 


Wood may soak up water and then swell, and glass terrariums/aquariums are not infinitely sturdy, so try not to have a straight piece of wood reaching from one pane to the opposite pane (your layout looks fine itr). 
I you have an L-shaped glueing area (i.e. a platform plus a ramp, fitted together as one unit (the L being along-and-up) or a platform in a corner (the L being along-both-panes)) any silicone should be able to carry your platform and your hamster. So you could have the two edge platforms and then an assembly of the middle platform well-attached to the two ramps. No pillars needed.


Silicone can be removed from flat and non-iced glass perfectly with a razorblade.