1 Humidipak will do it. go with the 15 gram, should last a year if using the travel humi occasionally. A larger Boveda would last for 2 years, maybe more.
One piece of advice if you go Xikar. They have no pressure release. If you check it you will need a crowbar to open it. I learned this the hard way. The lack of stablized air pressure below cabin in a plane seals it and seals it well. Other than that I love the 10 count I have.
Actually I heard at the first RTDA that they appeared this was a huge problem that they had to drill into them to get em open. Soon after the presure valve appeared. I remember hearing that story, not sure if it was true or not, I wasn't there. Funny if it is.
Regarding the lack of pressure release on the Xikars. With my 5 count, whenever it happens, I have used a credit card or a hotel room key card to pop it open. Works pretty easily.
That is true if you are gone on a week long trip or longer. But I've read many places that if you are just doing a quick weekend trip, distilled water is just fine as the seal is so tight anyway. I know a lot of people don't want to open a humidipak for a weekend trip and could get by with distilled water, but you would know a lot more than I would!
I believe he meant take it out of the origianal packageing. Once it is out you are on a time line until it dries up. but in an air tight caddy, mine has lasted over ayear under the bottom tray. When i open it for a trip it is good to go at 65%