Yes, some do store better than others.

I wouldn't push the temperature limits. If you freeze them you'll lose them. If it's too warm they tend to rot.

yes, some do store better. I have been storeing them for about 5 yrs. I wait till first frost, if poss., I live zone 6. then I dig them up. cut off all green, I make a bucket of diluted insectcide last yr I used spectracide/triazicide concentrate.I wash them in this mixture to kill all poss. bugs ,lay them out to dry,layer them in old wine crates ,paper on bottom, mulch then put the tubers in box and cover w/ more mulch. tubers do not touch ea. other,label & put in basement. lightly water in jan. bring out to garage in may.lg. or dinner plate dahlias do best.also do this w/ calla lilly and four-o- clarks and canna.I have had good luck. this yr i'm going to try sulfur too. smaller ones i've tried did not rot or bloom. do not over water in winter,actually better not to water than over water. hope this helps.every yr. they get bigger and form babbies.mc1720161318099ec rosa abbystractkat@cox.net.