The crossed centre pair should not matter really, but my usual habit on RJ11 leads is to not cross them over at all,
Blue with white stripe goes to the exact same pin number at the other end
So do what I said originally and you should be fine. The note working in that thread is probably down to what looks like the sort of extension cable to avoid these days.
If doing a few crimps regularly then at a basic cable tester
is worth considering. A good few times when putting crimps on cables in dark dank corners I have messed up and testers can save time.