I bought 24mm Panoptics because their field of view (aperture stop) almost exactly matches the binoviewer, so you get the widest possible field. I'm very happy with them. Haven't tried 19mm so can't tell you how they compare.
I agree with Sergio. Go w/ the 24's. I have a 14.5" Starmaster f/4.3 and power switch. I do most of my viewing w/ the lowest power setting for widest FOV and occasionally go up to the mid-power setting. The highest power setting will generally be too dark. For that reason alone I don't recommend the 19mm's. I usually don't use the highest setting unless I'm trying to split a close double star. The 24's are perfect for any binoviewer set-up. Jim