Hey guys. I'm putting together a city/racing bike hybrid and the 90s Chinello frame I'm using has a few interesting issues. The one I can't seem to work around is that the ferrules for the derailleur cable housing don't fit in the cable stops at all. In fact, the cable stop is so snug that the housing slides through the chainstay cable stop very tightly, leaving no room for a ferrule of any kind I've seen.
The cable stops on the downtube can facilitate a ferrule reasonably well, though it's not quite as snug as I'd like. Here the narrowest part of the hole also allows me to slide the housing through quite snugly.
Now, I've thought about just routing the cable housing all the way from the derailleur to the grip shifters without having the inner cable exposed at any point, but then it won't fit in the guide under the bottom bracket.

What do I do?

(another thing- is there an elegant solution to mounting a mudguard/fender on a front fork that doesn't have any mounting holes whatsoever?)

Thanks for your time...