that looks great!!! But do worry about loose seams. They will give you more trouble later. I had the problem one time. I called my dealer and got to speak to the actual repair guy!!!!!! He said there was almost certainly lint or a smidgen of thread caught somewhere. He said to notice where the thread tensioner was, for reference, then open it all the way up and clean in there. Yup, 1/2" of shredded thread. there was also a bit of lint under the bobbin case's tension spring. I ended by doing a massive cleaning finding tiny bits in several places. The combination gave the sort of off and on tension problem you are describing.
I agree about using Stitch in the ditch to control wobbles.