Great collection of artillery you have started there, ACW guns can be like potato chips...you can't eat just one! Just ask Mike and Chris, I think they have many of the 1st Legion artillery figures along with the W. Britain and ONWTC artillery, and they seem to work very well together.
By the way I modeled the earlier removable brass sight for the gun over eight years ago when we did the Loomis Battery (1st Michigan Light Artillery Battery A) set for ONWTC. I measured an original Parrot and carriage surviving from that unit (No.23) to make the pattern.
Here is a picture of the old ONWTC set, occasionally these still appear on the secondary market.
Thank for sharing the pictures of your collection with us,
Ken