If you overseeded (which would be now to two weeks ago for a KBG overseed), you can feed around October first, and again in November and skip the September feeding, no problem. By October, the new grass seed will need a feeding anyway.

"Dare I hold off N completely until next year so that I know I'm not pushing growth versus letting roots establish."

That would actually be a bad move as the new grass also needs a feeding to establish. That schedule above will be good for establishing a new grass. For bluegrasses, they're fairly hungry. All the time. Shorting them of food really isn't a good idea, although skipping that overseeding feed is understandable.

Thx. Did not want it to -push- blades when I want roots.....afterall, it's still sited in non irrigated - sandwiched on a hell-strip. WIth current CV19, I don't think I will be on the troll for leaves recycling and me taking them back home this year....for all the leaf mulch I can make.

Not to over-simplify this statement, but yes, I do concur that even after a few mows, the grass blades are still new/thin, but always after the 1st feed, I swear, the transformation of the blades look like they become much more mature

"Did not want it to -push- blades when I want roots"

You won't and there are no worries there. The magic transformation after first feed is because first feed is usually at the one month mark...when the transformation starts to happen anyway and the grass plant drops the embryonic blade and grows its adult blades.

Heck strips are just a challenge no matter what and, for first-year grass, you're probably going to have to irrigate a little bit no matter what. For the first two years, the roots aren't that great and dormancy mechanisms aren't that well-established. We mow too short.