I haven't done that race, so don't have any idea about ground conditions. In general, I prefer more volume but your frame clearly doesn't allow that. I find Contis to be pretty true to size so surprised to hear you think they are large - some of it depends on your rim width / shape.
Perhaps the ProRace Endurance or Service Course models in 23s which are relatively high volume 23s with better flat protection. That might be a good recommendation. Mich 25s are too big.
There really isn't much more too it than that given your set-up. If you can't realistically get 25s in there, you need more plush 23s that are a little flat resistant but still roll well.
Also , I agree with other posters in that slightly reduced air pressure is good. I don't believe everyone needs 110 in a clincher for 23s - you can go lower if you are not too heavy and get some off road compliance but you do risk pinch flats if you go too low. Just going down to 90 is a benefit I have found.
Last thought - just invest in some new Contis right before the race. You were happy with them, and they worked. When they stretch, move them to another bike or gift them to a team mate, etc. Or go 23 / 25 front / rear depending on where you rubbed.
j
Perhaps the ProRace Endurance or Service Course models in 23s which are relatively high volume 23s with better flat protection. That might be a good recommendation. Mich 25s are too big.
There really isn't much more too it than that given your set-up. If you can't realistically get 25s in there, you need more plush 23s that are a little flat resistant but still roll well.
Also , I agree with other posters in that slightly reduced air pressure is good. I don't believe everyone needs 110 in a clincher for 23s - you can go lower if you are not too heavy and get some off road compliance but you do risk pinch flats if you go too low. Just going down to 90 is a benefit I have found.
Last thought - just invest in some new Contis right before the race. You were happy with them, and they worked. When they stretch, move them to another bike or gift them to a team mate, etc. Or go 23 / 25 front / rear depending on where you rubbed.
j