Your plant looks beautiful and so healthy. Congratulations!
I've only had mine for 3 months but they were advertised as 2-3 years old. The tap roots are curvey, about 2 - 3 inches long and a bit over 1/4 inch diameter. Does that sound about right for the size?
I repotted mine in a larger pot with lighter soil, added 25% perlite to my mix so I'm thinking my mix is about 38/72 soil to perlite/vermiculite now. I just now replaced the top 1/2 inch with pumice.
I have only exposed them to filtered light but it looks like yours may be in direct sunlight. How much sun should they have? Watering - how much is right?
They've been in my greenhouse but I'd like to put them outside. Do you know if animals will try to eat them? Lots of squirrels visit my yard.
Sorry for so many questions but I'd like to repeat your success.