.51 vs .74 Grace Duo

I am thinking about picking up a MLD Grace Duo for use on short trips. Trips may be 1p, 2p and sometimes include my 30# dog. We usually cowboy camp in lightweight bivies. The tarp only gets set up if rain threatens or during heavy wind. I have a Duomid XL that I use on longer trips or heavier weather. Trips will primarily be in the forests in AZ but it’s possible I’d take it to the Sierra when I’m feeling confident about the forecast. Tarp will be used in 3-season conditions.

Given all that, I’m curious to hear any thoughts on .51 vs .74 DCF in this application. It’s a 2.5 ounce difference and perhaps packs slightly smaller. The reality is that this tarp won’t see many nights (I’m not doing a major thru with it and it won’t get used on many nights where we just cowboy camp). .51 doesn’t seem stupid-light, it’s used in many thousands of ZPacks shelters, right? Any thoughts on .51 for my proposed use?