QTR-Quadtone RIP

I am hoping someone in this group might be able to give me a little
advice...
I am attempting to print digital negatives for silver prints. I am
printing on Pictorico White Film on an Epson R1800 using the K7
Piezography inkset and QTR.  The problem I need to solve is I have
banding in the sky in my images. At the point of almost giving up, I
found this article (link below with attached .pdf) 

http://www.digital-negatives.com/index_quadtone.htm

To summarize the article, it is from Ron Reeder, one of the authors on
a great new book "Digital Negatives". He describes that in his High
Key images he also had banding in the sky.  He goes on to say he spoke
with Roy Harrington at QTR who helped him in writing a QTR profile.

I realize Reeder lists the steps to create a QTR profile for OHP film
for a Epson 4000 using Epson inks for Palladium Prints and not exactly
what I need.  But it's close, I think I could solve the banding
problem if I too could adjust one of the K7 QTR curves. So this is
where I thought I would check with this group for any advice because I
realize this is going to be tough.  Any help would be much
appreciated! Thank you so much!! -Victoria