Question about food container as Humidor and Heartfelt..

I'm trying to find a good setup that will keep my cigars safe without breaking the bank.. I got suggested using the airtight food container! which I find really great price wise.

So I thought of getting one, and add 1or2 Large HeartFelt beads tube and their small aluminum humidifier in it and thats it... with a hygrometer.

My questions are;
1. Now which is better? the tempered glass ones or just regular plastic ones?
2. Do I still need to "season" the container? Since its glass and not cedar/wood I'm assuming that I don't really need to season it!?
3. How do you guys choose between 65% and 70%? All of the stuff I have and would get are Cubans cigar... How would you explain the difference in taste-experience with a cigar stored @55-65% and @65-75%...

thx in advance!