I would think twice about dumping that Mexicola. Based on my initial tastes and what I've read I'd take the Mexicola over the Joey any day. Here's a pic of one of my Joey's:
Ever noticed how all you see are jazzy marketing write ups by nurseries but few have tasted what I call the "Tex-Mex" avocados? Wilma, Joey, Fantastic, Brazos Belle et al. One Texas grower said Wilma tasted like grass.
He hates it and only uses it for rootstock.
Funny but I'm starting a Joey seed with the intent to graph Mexicola or Stewart to it. BTW, once old in age, Mexicola has taken temps down into the single digits, this passed on to me by a seasoned tropical fruit grower in Texas who witnessed it.