Wow Brad, that is a massive fruit for a tree that young! I’m curious to hear if it kept enough of the parent genetics to remain an ‘improved Kent’. Let us know how it tastes when ready. I’ve been impressed how many of my monoembryonic seedlings have retained the favorable genetics of their parents.
Regarding your Sweet Tart seedling, I still think this variety is one of the very best to grow in CA. It consistently gets rave reviews, is versatile in harvest timing, and grows vigorously. If seedlings give similar fruit, they should be in everyone’s yard.