I have QF in part shade. The leaves burn in the summer here if I try full sun.

I'm trying to figure this out myself. I'm curious as to what would be the minimal amount of sunlight a paniculata can get and still look good. I have a lot of areas that get maybe an hour or two of direct sun and then dappled sunlight from sunup til sunset. I'm hoping I can still use these spots. Sorry I haven't answered your question. But thanks for asking mine :)

To find minimum appropriate sunlight for your zone I would suggest growing one in a large container and moving it to a different place for a few years. You could try something like 2-4-6 hours of direct sun per day over three years and make a chart showing growth and bloom count, etc.

I have some Little Lambs in full sun and some others in partial sun- sun until maybe 10 am then dappled on and off.
The ones in full sun bloom a couple of weeks earlier but that's the only difference I have seen although the blooms stay nicer longer in the shady zone.

Actually, the ones in the shade were just put there because I didn't have any where else to put them- at the time it was a temporary holding area. But they settled in and seem to be very happy so I left them.

I have a 2 QuickFires and 2 Limelights in 4-6 hours direct sun. Quickfires look great and are just a little behind the ones in full sun. Limelights bloom about 33-50% less, smaller blooms and flop bad in heavy rains. Although I still enjoy them. I think if I had an eye shot of the ones in full sun at the same time I dont think I would. Also they are 3 going on 4 years in the ground. Hoping as they mature they will do better.

Thanks folks, I'll give Quickfire a shot in the part shade locations. I've always like that plant and they are too vigorous in these parts.