So the new frame I built up I tried to fit a 25mm challenge tire on a 22mm internal width rim and there wasn't enough space to make me happy, the tire measured 28mm wide on that rim. I've since built velocity a23 and have put 23mm Conti on it which I pumped to 90 being a heavier guy. Riding down the street has felt very smooth, grippy and nice and light to throw around. On this rim it measures about 24mm and the wider rim makes it feel nicer than the old open pros did, feels faster too.
i did like the ride of the challenge and will be building the rim with a match into my original race bike which will easily handle the wider width. Admittedly the combo feels fairly quick and nimble as well but not quite as nice, but will do well for the rough roads I prefer riding the steel frame and fork of the old bike on.