I look forward to you explaining your justification for using an iPad whilst driving. Taking notes in flight! lol, study aid? log book entries, why would you need to fix it to a window for this? It should be stowed when not being used and why not pop it on your table when using it.
The only reason for mounting the device is to use it as an EFB and if you were authorised to do that you would have appropriate mounting points and procedures. You obviously don't have those and so have no justification for modifying your cockpit.
Think for a moment about your suction mounted iPad falling off on late finals.
and here's a link to the sort of information you as a "Skipper" should be aware of:
http://www.nbaa.org/ops/cns/efb/2011...-76b-draft.pdf