According to this pdf, the conditions that are created by installing a greenhouse will bring the climate very close to the ideal temperatures, especially in the winter. I think letting the greenhouse get below freezing may be a waste of valuable growing time when they would be better off in the 1 to 12C for vernalization. The only drawback to having a greenhouse is that it also blocks out all the rain water so it becomes necessary to water all the plants inside around once a week.http://bamboonetwork.org/downloads/chinesemoso.pdf
Hardiness
Moso bamboo is located in hardness zones 7, 8, 9 and 10.
Zones 7, 8, 9 and 10 have mean annual minimum temperature
-17.7 to -12.3°C (0.14 to 9.8°F), -12.2 to -16.7°C (10 to -1.9°F),
-6.6 to -1.2°C (20 to 29.8°F) and -1.1 to 4.4°C (30 to 39.9°F)
respectively, but the central distribution zone is in zone 9 and
8. Moso bamboo grows naturally in subtropical monsoon
climate zone (in summer high temperatures and rainy; in
winter cold and dry). The mean annual temperature varies
from 15 to 21°C (59 to 69.8°F), with a mean temperature of
the coldest month being 1 to 12°C (33.8 to 53.6°F), the mean
annual minimum temperature ranging from -1.2 to -18°C
(29.8 to -0.39°F), and that of the warmest month from 26 to
29°C (78.8 to 84.2°F). Moso bamboo can withstand -18 to
-20°C (-0.39 to -4°F) in the winter. The annual precipitation is
between 800 to 1800 mm (31½ to 71 inches). The restricting
factors for Moso distribution are the annual precipitation (800
mm or 31½ inches) and minimum temperature in winter in
the north, and drought in spring in the south. Spring drought
makes shooting difficult.
I also found a pretty good video on solar greenhouses. This guy is claiming 21F of temperature differential with his setup going from 19F to 41F which is around 5F better insulation than what I've gotten in the past through the night. Some of his tricks were covering up the entire glazed area over the night, frost protecting the plants inside, and additional layering where heat tends to escape which is not that hard to replicate.
As far as taking care of the CO2 problem, I already have a rotting log in there, but one thing I plan on doing is sticking a large bag with saw dust & manure, then throw in some of my shiitake, and reishi mushrooms as well as some of the wild species to make sure that there's a CO2 generating mass of materials in there. Keeping 1 zipper open should be enough to help the air circulation.