Just an update as I finished my MHT-DTW-MSY journey today. There is inconsistancy (surprise!) in the way TSA is handling the secondary / gate screening. Apparently some airports open every bag and rummage the bags at the gate but I found some just mentioned to you at the gate to dump any liquids you picked up in the airport and left it to the honor system to dispose. Some TSA opened all bags at the first check point, some did regular screening there but opened them at the gate. May all depend on staffing issues, but it's not worth losing any valuable or essential toiletries.
Security is messy though, so come to the airport early. Once you clear security, connections went pretty well. Things were just a few minutes delayed in both DTW and MEM.