Can't tell if starter is ready for baking/fridge - everything seems right except it doesn't double
So my starter is (almost) exactly 2 weeks old. I started it with 100% WW flour and have since been feeding it with 50% WW + 50% AP in a 1:1:1 ratio (100g each of starter, flour, water) twice daily. It went through the expected surge of activity on day 2, then seemed rather dormant on days 3-6 but it did have small bubbles and a sour smell and taste. From day 8 to now its daily cycle and look have been very consistent - it has bubbles visible on the sides and top, the top is very bubbly, kind of frothy even when it's time to feed it, it smells like apples and tastes pleasantly sour (the bubbles and taste/smell are at peak intensity at feeding time; they're a bit more faint when the starter is at its max height). It reaches its maximum at 7h after feeding and then falls. Thing is, I've been measuring the rise (in addition to using a rubber band around the jar) and it only ever goes from 35mm to 58-60mm, so only about a 70% increase, not fully doubling. Everything else seems spot on and has been happening like clockwork twice daily for almost a week now. I also did the float test a couple of days ago and it did float at first and then sank after a little while. It's being kept at room temperature which is around 24C right now. I've researched this a bit and some people have said that starters don't absolutely have to double, some do more than double and some never quite reach that point, also the width of the jar might have something to do with it (while I wouldn't describe mine as wide or anything the ones on the KAF and TPL starter guides do seem narrower). Basically, I don't really know where to go from here. How do I know when my starter's ready to be maintained in the fridge on a once-weekly feeding schedule? Should I keep doing what I've been doing, add in some rye flour, change the jar/feeding ratios/something else? As far as baking goes, I guess I can just try and see what happens, the first loaf is unlikely to be anything good anyway, but I'm more confused about how to go on with the maintenance part.