Hi Patty! I zapped my T2D over about 6 months, basically via weight loss in line with Roy Taylor's stuff, though without doing the 800 calorie thing. (As he says, it's not so important how you lose the weight and for some people, for example me, grinding off half a kilo a week over a few months may be the best approach.)
So I'm obviously an enthusiast for the approach. And his book has IMO a really, really good explanation of what's actually going on with glucose metabolism in T2D.
I never used a BG-tracking app but did test a lot and record readings in a spreadsheet. It lets you focus on the trend, rather than the day-to-day noise. Particularly in the early stages, readings can vary a lot, day-to-day, which can be discouraging if you're not tracking the trend.
This is a picture of my path-to-normal, in terms of daily average BG:
View attachment 15933
Lots of ups and downs, but fairly clear trends, which is what you should focus on. Good luck!