Here is a quick and easy cheat
Add one of the default arena fields, and within the editor, "select" the maproom and everything within it by dragging the selection box over the entire maproom.
Then "Save Object Group" to a name like Maproom.
Then you can delete the airfield you werent' using.
Now when you want to add a maproom, just add the maproom object group.
Easiest way.
PS: I haven't seen the clipping problems, could you describe how and where your seeing them?
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Vermillion
**MOL**, Men of Leisure