I'm not an "aeration expert" by any means. However, when you say your aerator is "running wide open NOW", I'm concerned about how you ran the aerator prior to "now".

I've seen folks install aerators in mid-summer, then flip the switch and walk away (i.e. "24/7"). This tactic often causes an acute mixing of "bad" water with "good" water. If there's more bad water than good (from a DO standpoint), the abrupt sum of the two might pose issues to fish that are sensitive to low DOs (catfish; though tolerant to relatively low DOs, are not immune to suffocation). The best approach is the gradually increase the aerator's run-time (2, 4, 6 hrs/day, etc) so any mixing of water-column DO-variables occurs slowly over an extended period of time.

Regarding your Cutrine rate: .6 ac x 5' avg depth = 3 ac-ft of water. Cutrine's labeled rate calls for .6 gal/ac-ft; ~ or 1.8 gal for 3 ac-ft ~ but only "IF" you were treating your entire pond at one time (NOT RECOMMENDED).

Personally, I don't like nor agree with the label's vague and possibly misleading language - BUT must admit that listing "prescriptions" (dosages and application technique) to cover all possible algae-scenarios is completely impractical.

Your 2/3-gal treatment around the perimeter seems reasonable. However, so many variables come into play when discussing "safe treatments" that it is impossible to guarantee acceptable results - OR, for that matter, the absence of fish-issues.

My strongest suggestion is to always take SMALL STEPS when implementing ANY changes to your pond's environment (algae, weeds, DO, clarity, blooms, etc). Fish can usually adapt to small, gradual & incremental manipulations of their habitat; but often croak in response to any abrupt or massive alterations.

As for your general plan; it sounds good, providing that you don't alter too many things too quickly.