I'd go with the weaker fert for a newly planted Hib and also use about half as much as they recommend for the first application. Don't want to burn the new roots that will be forming. The other formulation looks a bit extreme to me. Maybe try it on one of your other established Hibs first to see what happens?
The other thing they absolutely require is acid soil, and being at the base of a concrete block wall, I'd advise you test the pH of the soil before you plant. Concrete can leach alkaline stuff (lime, I think) over time with rain and watering. Since you definitely will need to water your new Hib in So.Cal you don't want to have it struggling for nutrients because of a high soil pH. If you still want to plant there, amend the soil with lots of compost and maybe some peat, and think about painting the concrete block with something to seal it against further leaching. (you could do a mural with leaves to further disguise the ugly wall . . . or just something clear)
Afternoon sun should be ok, as long as it's getting enough water when the weather is really hot.
