Mut also strikes with both weapons at the same time, so assuming DP has an even chance to apply with both weapons in the new world of poisons (pretty sure it does), you are getting two buffed chances to apply DP in each envenom if you pool first.
If your SnD is going to fall off it is probably better to envenom early to refresh it. We are energy starved beyond belief right now, so getting two muts in an envenom isn't always going to happen. It's a good thing to try for though. If you spec Anticipation, you can blindside at 5cp while pooling and not worry about losing the extra CP.
Get a good buff/debuff timer (I use Rogue Power Bars) and get a feel for watching them. Sometimes it feels like I'm healing again and I get tunnel vision on my timers ... try to put them somewhere on your screen where you can glance quick and see them, but not so central that you'll completely focus on them and start Standing In Bad Things.