I'm currently using an Enlightened Equipment ProdigyX TQ with a Hennessy double-bubble pad in a Hennessy Expedition Asym Zip.

At 30° I wake up with painfully cold feet and am shivering all night. I feel warm on top but it's cold underneath me. I think it's time to go for an under quilt. JrB seems like a popular choice and I've got a couple Qs:

1) given my cold feet, I'm thinking about going full length. It gets cold in Arizona at night. I'd like to be comfortable to 20°. Am I crazy to go full length?

2) which full length JrB UQ fits a Hennessy zip best? Nest or Mt. Washington?

Any advice would be welcome.

Background: I'm a scouting father with a base weight in the 25+ pound range doing one/two night trips walking 1-8 miles. No thru-hiking.