combining a WM Megalite and a WM flight Jacket

I was wondering the same thing the other day and looked over the readerbreviews for various bags here.

Eric B, who is a current poster here did a mid 20 degree? test with his Megalite and did just fine..You might go and look at the details of his review and test.

I would think the flight jacket along with a thermo bottom and decent hat/ beenie would get you down to the mid 20s ok for a few hours easy.

I have done 20f with the similar Summerlite, merino top and bottom ,light socks and gloves and merino hat as well as WM Flash jacket and pants.
The Flight is warmer but you might still need some extra bottom insulation (pants)and you will need a warmer mat.
I prefer using the Exped DM7 but have used the original Neo with a home made LW mat under it.(a thin CF will do)
I like that layering better than just using a warmer bag because I can regulate the temperature better from our typical around 30f at bed time to down to 20f or so at 4-5AM.
Works well for my regular once a night view of the sky.

Thanks for that insight..I was looking at the Summerlite as well. Good to know a bit more about its capabilities.

I am leaning hard towards the Megalite due to the extra bit if girth in the torso.

in 2009 I slept at 11,000 ft. at 15 F. in my Megalite with a Thermolite Micro insulated jacket and pants and was very comfortable.

Now with my Megalite overstuffed by WM in 2011 it could likely go to at least 10 F. with the same clothes or my Eddie Bauer Downlight jacket (avatar photo).

I'm planning to get a quilt to top my Megalite for winter and temps to -20 F.

Yes , for layering you need some wiggle room, I have enough in the Summerlite.
Nothing new by the way here, just an extension of going to bed with what you have (except I prefer clean/dry stuff , when possible) something that in modern times climbers with their elephant foot/puffy top combo have been doing for decades.