I have the Airfix 1/24 Hurricane.

However I am a long way away from starting the build. Maybe years away.

Anyway, I plan on tackling the camo freehand...meaning no pre-made camo masks.

The pattern is well documented, you can find plenty of reference for laying out the design.

(I'll probably use an enlarged paper pattern like you suggested)

I really don't know if this pattern was originally applied using stencils, (I'm going to research this).

It probably was, although it may have been a freehand paint application, in which case no two planes would be exactly alike.

Very similar, but not perfectly alike.

There's probably someone on ebay with a stencil mask, but probably not cheap.