Rio's & Kemens are both fine, but I have to wonder why you wish to bother with a 1oz. 28ga. load .. they are much like the 20 1oz loads .. ALWAYS slower than the standard shot charges at 1200 fps, higher pressures 100% of the time and if you are going to shoot much of it at all, a real pain in the shoulder if the gun weighs anything less than 7+ pounds. With lead shot, I do not see any advantage or need for more than 3/4oz in a 28Ga, or 7/8oz. in a 20. My own patterning experience says the heavier charges are less effective on the plate than the standard loads too. My personal experience w/factory 1oz. 28's is limited to the very old Federals, but with the 20ga. it covers a number of the 1oz. loads from assorted manufacturers ... less is better in either gauge. I also did, at one time, a fair amount of patterning with listed H110 1oz. reloads in 28ga. Aside from significant recoil their was nothing remotely impressive about them. A number of the original Remington 1148 28ga, guns were hammered to death with the old 1oz. loads. If I'm not mistaken that is the reason that no American Mfg. continued to offer them. If you are looking for lower pressures, 1oz. is not the way to go. All small bores tend toward higher pressures, so the term 'low pressure' is a bit misleading, but lower pressures can be attained with some combinations of componenets. Factory rounds are going to be within industry specs, and that means at the high end, as far as I know.
I do not question the quality of the make [Rio] you are inquiring about, but I would steer toward the regular target loads instead of the 1oz stuff. Target loads will tend to have have the highest quality shot available to the Mfg, regardless of name and they will generally produce the best patterns as well. Just my thots.
