You might get some differing opinions as both the 5-1-1 or the gritty mix will work perfectly well and each has their advocates. I prefer the 5-1-1 as it reduces the need for me to water quite so frequently in summer. And that might make better sense for your purpose given the windy exposure.

Personally, I wouldn't let Miracle Gro come anywhere near my containerized JM's unless a small portion was used in place of the peat or coir in the 5-1-1. It is far too water retentive and collapses or compresses far too rapidly so the need to repot and replace soil would be annually rather than the more typical 3-5 years.

Basic 5-1-1 mix:

5 parts bark fines

1 part peat or coir (or commercial bagged potting soil)

1 part perlite