Thanks for the ideas. Yesterday I went tree shopping and came back with Brogdon, Simmonds and Oro Negro. I wasn't planning on buying the Brogdon, but I tasted the fruit and really enjoyed it. The texture was creamy without being mushy, and the flavor reminded me of whipped butter. Far superior to the Mexicola Grande's mild and washed out taste, plus the fruit is larger.
I will replace the Mexicola Grande tree with the Brogdon which will give me better tasting avocados at the same time of the year (late summer) and add a Type B tree.
I will move the Wurtz tree (hopefully it survives) to a spot along the house since it's staying so small and plant the Simmonds in the hole. Then I will add the Oro Negro (also Type B) and Lara-Pollock to the row which will give me:
Early season = Simmonds, Brogdon
Mid Season = Super Haas, Lara-Pollock
Late Season = Choquette, Oro Negro, Wurtz
Then I can graft on a few branches of the other varieties and have a fairly complete selection: Ronnie, Kampong, Lula, Catalina, Hialeah Red, Dupuis, Miguel.
How likely is the 3 years in the ground (and 3 feet tall) Wurtz tree to survive being moved? Any tips?