My Wondfo's have showed up a line only around 10-11DPO, but they showed before a FRER did for me (for both my CPs). I've never tried dollar tree because every time I go they are out but I've heard they are the most sensitive.
My CM is mostly gone, so I'm expected AF in a day or two. I'm thinking it'll be a couple days later, which means that maybe my LP is increasing on its own? That would be nice. I've heard it doens't just change, but I'm still only 10 months off bcp and I've been told to expect it to take up to 1 month for every year you were on bcp. That's 15 months! Haha.