As far as I can tell there are at least 4 different types of suite reservations that may have restricted availability:

Paid booking (any available rate) + Diamond suite upgrade
Paid booking (Hyatt Daily Rate) + 6000 points suite upgrade
Points redemption (8K - 33K points/night)
Chase Visa Diamond free suite nights

It's not entirely clear to me which of these are subject to "last room availability" where if a suite is available for sale, it's available for redemption/upgrade.

Recently I have been trying to book a suite points award at the PH Washington DC. Every time I have called, the agent offers me:

- points booking into a regular room (22K points/night)
- 6000 points suite upgrade paying the Hyatt Daily Rate

But they all insist that the points redemption for a suite is not available (I am booking for the 3-night minimum required for suite points redemptions). The suite is available to book for cash, and also for suite upgrade. It seems that points redemptions for suites are capacity controlled in some manner that is not transparent to users. So a few questions:

1) Am I correct in assuming that suite points redemptions are capacity controlled?
2) Is there any way to identify availability short of calling Gold Passport?
3) Any hints or tips to snag the suite award I want?

I can't help much with your query, but I have seen instances where suites were not available for sale, but were available for suite upgrades.

1 - I believe so
2 & 3 - No.

An excellent Diamond benefit would be knowing if NOR1 upgrades are happening 24-48hrs in advance

Well that's a bit disappointing. Good to at least confirm my assumptions in any case.

NOR1? Is that Hyatt?

Contact the property directly.

Hyatt and Hilton.

If a Diamond Member, I would try a manager at the hotel property.