sleeping warmth test?

So I am currently in the woods off trail a 1/2 mile from my car with my sleep setup

Including my bivy, two 40 degree sleeping bags, base layer clothing, pads etc.

I have been wrapped up in here 30mins and am pleasently warm. I have high cal,no cook fatty foods at the ready

We are currently exsperiancing a cold snap here in MT and its five o clock and 30 degrees

If the normal overnight low were to be 30 would I be warm all night?

I feel nervous going on a trip w/ an untested system what suffices as a good test?

Forgive the crude format as I am on a blackberry*shame*