Peter calls for holding the wheel overnight at 50F after pressing and then brining 12-16 hours for a 4 pound wheel. I brined immediately after pressing for just 6 hours. My rationale was to keep the rind pliable, and I didn't want a high salt content to inhibit the Propionic bacteria. (The finished cheese was NOT lacking for salt).
AFTER brining, I air dried at 55F for a week and then moved it to a warm room temp of 68-70F. Visible swelling started within just 2 days. After 10 days, it started sweating. I was concerned about losing fat, but it apparently was a good thing. I think a higher temp above 65F is VERY important.
I wanted to call these two details out because I want to emphasize their importance. While pressing under whey, hitting pH targets, wheel surface/volume ratio, etc are also important, it is the affinage that makes this cheese work because this is when the Propionic do their work. The optimal temp for propionic (highest volume co2 and propionic acid produced is about 30 C, which is 86 F. However, this is too hot for lactic bacteria and produces defects. So a tradeoff must be maintained between high propionic activity and the rest of the cheese. This to me is somewhere around 70-75 degrees. If it's too cool, the gas production will be slow, and the end result will be smaller holes and less propionic flavor.
The second important item is the salt content. Propionic bacteria are very sensitive to salt. Whereas a cheddar needs 2.2%+ (depends on fat content), a swiss does best at around 1%.
The third item is rind plasticity. This cheese swells. The rind must hold. Francois has mentioned he paints his swiss cheeses with PVA, which is one way to help with rind plasticity by introducing a protector. If you don't want to use PVA, one option is to use a less concentrated brine not at full saturation. This will also help with the salt uptake and dispersion throughout the cheese.
The fourth item is drying the rind and building it up before aging in warmer temps. Again, this is part of rind development so that the cheese does not burst. It doesn't have to be a week at a lower humidity and temp, but the rind needs to dry a little. Waiting before moving to warmer temps also gives the cheese body a chance to come together more and fuse. So what's left are small mechanical inclusions and fissures that serve as the seed points for the co2 to come together and make holes. Some emmethaler cheesemakers wait as long as 2-3 weeks before moving the cheeses to warmer temps.
This is just the science talking for anyone interested in why this cheese turned out so well. Sailor has posted some great practical guidelines for making this cheese. Kudos and thanks