Originally Posted by
velonomad
Twitchy when? going slow or fast? Touring bikes traditionaly have less steering trail and will feel more stable at low speeds. Unloaded touring bikes often (IMO they should ) feel "twitchy" at higher speeds since it's intended use is for touring with the weight of panniers and handlebar bags. Sorta like a pickup truck rides better when it is loaded down.
There is a tradeoff, You might reduce the twitchy feeling somewhat by using the 50 mm fork but if you later add 50-70lbs of touring weight for a tour, the steering will likely feel heavier. If you ride the unladen bike enough you will likely get use to the sensitive steering by learning to use less steering input
My opinion about lower trail (55 mm offset) versus higher trail (50 mm offset) is that stability is affected. I have a few touring-ish bikes, a Trek and a Woodrup, both with lower (45 to 55 mm) trail, and both with sensitivity to crosswinds, road bumps, and fidgety rider actions. I don't ride with heavy loads, so perhaps I don't see the advantages. What I prefer for my riding are '70s and '80s road race style designs, such as my Mondonico and Masi, which each have around 60 mm of trail if not a bit more. The steering on these requires a decent 'bar effort, but the bikes respond fast, well, just because they do.
I would tend toward the 50 mm fork. One side effect will be reduced vertical fork flex, a little more road jitter coming up through the handlebars.
Road Fan