You could use 2 half filler peices together instead of cutting at all.
I am glad you can order your peices Flatcat!
I too am trying to build up a castle, but US DS hardly has any pieces,
Especially not steck pieces... I have asked.
So I would try another DS if you live in the US.
If you dont, and are already ordering from another DS, lucky you!

Which reminds me... (I hope I am not getting too off topic...)
What are the phone numbers for the Canadian DS, or the England DS...

If you have the emails that would be even better!