Josh,
For the places you need to cut headliner you might consider going to Ace hardware or a big box store and looking at their selection of plastic hole plugs first. If you can measure carefully you may be able to use a properly sized hole saw to gain access to nuts on bottom side of deck through headliner and the use hole plugs when finished for a fairly attractive and painless completion of work. Just an idea.
Bill Walker
CbC 36
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