Pine to South Rim Grand Canyon (Low Temps)

I delayed my trip to the middle of May due to reports of lingering snow and am heading out NOBO from Pine in mid May with the goal of hiking to the Grand Canyon South Rim. From my research, it seems like low temps are likely to be in the mid 30s to low 40s depending on elevation along that section for that time of year. Does this seem about right? I'm debating whether to take my 10F ZPacks quilt-bag or my EE 30F quilt. The weight difference is only around 7 ounces but with some longer water carries, I am trying to shave base weight where I can.

If you have a puffy jacket, take the 30º and I think you'll do fine.

Over spring break, I took a week long trip to GSMNP where I had my Mountain Hardware 32º sleeping bag, fleece pants, fleece vest, and a puffy jacket. By laying the puffy jacket over the sleeping bag like an extra blanket, I was comfortable with night time temperatures right at 40º.

Looking at the climate data shown on the GC web page, night time lows in May should be about 40º. But it seems like weather has lately been warmer than what these sorts of "climate average" show. For example, climate data for GSMNP indicates I should have been experiencing night time lows much closer to freezing while I was on my trip. If you look at the current forecast for GC, you'll see night time lows are currently more in line with what you would expect in early June.

So my personal educated GUESS is that you will experience night time lows of 45º, and with typical weather variations being about +/-10º... I expect you will experience night time lows anywhere between 35º and 55º on your trip.

I do have a puffy jacket (Montbell) that I have used in the past to supplement my sleep system and I generally wear smart wool base layers when I sleep. I like the idea of modular systems and layering to increasing the comfort level of a sleep system and feel like the 10F zPacks might be overkill. I think that I will check actual low temps the week before my trip and see how things are trending. I have some concerns about really long water carries so every ounce of base weight I can cut will count. Thanks for the input.