Here is a great heli tower build using shop front windows for the bullet proof windows.

[Invis]

This works really well as both a normal defence tower and a heli tower. Hope you all like the video. Keep in mind it recorded a little bad but I have a few other tips on my channel with good recording.

https://www.youtube.com/watch?v=j46ySOdQSms

[King Of Essex]

YOU SAY shopfront with bulit proof glass? i dont see that in my list ???

PS: my shop front has opening doors, not like your vidoe, have i missed something??

[David]

look harder its there for sure

[Invis]

You can find the shop front under construction tab of the crafting menu.