I've actaully done exactly what you are trying. I built the 1v on top of a 2v dome.
The 1v covering is VERY simple. If you need, go out and buy yourself a "D20" dice to help picture it. Its a 1v full sphere.
The side is just a straight bit of cloth. The triangles lean in and out equally and it all evens out.
The top is also easy. Draw and cut out a hexagon with the triangles the same size as the ones on your dome (v1's are nice that all of the triangles are the same).
Now cut out one triagle of the hexagon. You end up with something that looks like PacMan. Sew his mouth shut. You now have a "domed" pentagon that fits the roof.
Like this just without the extra triangles:
Seem allowances an such are up to you.
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Honey Badger don't care. Honey Badger don't give a shit!