Good point about the rim size. I hadn't considered the 3mm difference to be significant but I am used to motorcycle wheels.

The 25c rides very nicely, and makes the bike feel very snappy and smooth gliding. My main concern is that most of my road riding is done out in the country and I just felt that the 25c might be to fragile (lots of grit, buckled pavement, etc). Back in the day I rode sew-ups and got tired of fixing them - even the 8 oz training tire seemed too easy to puncture (I also remember wearing out my gloves trying to remove grit from the tire as I pedalled).

My thought was that the 28c might be a bit more robust, and is closer to the "oem correct" 27 x 1 1/4 size original (not that the original was in any way a performance tire!).

So I've flip flopped - I think the final choice will be made by what's the best quality tire I can get locally without breaking the bank.