Hats off to the handquilter! You have way more experience than I have at getting quilting done.
I handquilted one quilt - - straight lines. That is when I knew why ladies did some really intricate quilting patterns ... it was a matter of sanity!
It really is a personal preference, but I still like variety ... forget stippling! How about accenting each nine patch with a quilted something?
I would think the most important factor in how far apart your quilting can go would be your batting .... I have had batting that would allow me to quilt ten inches apart ... most batting needs to be quilted at least six inches apart ... check your batting package ... it would be a disaster to have a batting that highly recommends three inches, at the most, and then have your quilting on that outer row not fit that requirement.
Bottom line ... your quilt, your time, your fancy .... there are no laws of nature that you would be breaking if you changed your mind ....
I do that often ... exercising my female perogative ... changing my mind and doing something different ;-)