I’ve been growing mine on flying dragon since 2013 or so. I cover mine each winter as needed with 4 mil plastic, 32 gallon water barrel, space heater 250 watt regulated by thermo cube. I get 8 or large fruit off of it each year and they are very sweet and juicy for a grapefruit. However, although mine have a pink blush on the rind, the inside of the fruit is yellow. I got mine from Ben Salley at Simply Citrus in Columbia SC. He grafted it from the original Croxton tree. I think mine doesn’t turn pink inside because it doesn’t get very warm here at 3,000 ft elevation in summer. Similarly, my Rio Star grapefruit turns pink but not a full red. My Croxton has performed well each winter without die back using the method described, even one year when it didn’t get above freezing for the whole month of January. I just make sure to uncover it when temps get above freezing to keep it cold and dormant. I actually like the taste and texture of it better than the Rio Star.