I would not be too concerned over a one time higher dose of GHRP-6. Any significant increase for such a short duration will not bet detrimental to you in the long run. It would be different if you were constantly elevating both throughout a longer term.
On that note...
I like PS (Phosphatydilserine) the best for Cortisol control. Min of 800mg/day, but I tend to go with 1g (normally just in PCT or when low cal/Cutting). I personally do not like messing with 11BetaHSD-1 for cortisol control.
PS actually works on the hypothalamus affecting CRH and pituitary ACTH output.
This actually makes me wonder right now if the method of action of PS would be efficient on this level of the axis as GHRP will exhibit its counter action this level as well.
I am not sure if just blocking the exess cortisol conversion at the 11BHSD-1, from the GHRP mediated ACTH increase, would be the better route to go.
Anyhow, for PRL you could go with Cabergoline, which is Rx as Dostinex, BUT non RX if bought for Research. Its up to you how you define not wanting the non RX route
Best herbal/vitamin would be L-dopa (Mucana) or 1-Carboxy even though I believe they are the same (Lets not debate this one as its been overdone).
I would also add a good dose of EGCG and EGC from Green Tea as it is has been shown they are inhibitors of dopa-decarboxylase. You definitely do not want peripheral conversion of large amounts of L-dopa into dopamine as it will then not make it past the BBB and will exert its side effects systemically. (Last thing you are wanting right now is more BP issues I assume).
Also, other than that P-5-P (pyridoxal 5 phosphate) is great. The active coenzyme form of B6 (pyridoxine hcl) which will not cause the sides of higher doses of B6.
Sorry for the rant.
Take Care.
PS- I still do not think you need anything for this