Welcome to TE!
If your torso is short, the limiting factor isn't the stand-over height (since this is pretty fudgeable anyway) or seat tube length. Your limiting factor (and mine!) is the top tube length (or effective top tube length, considering these have sloping top tubes.) What's your inseam? I'm a little taller than you (5'6.75"), and I have a ridiculously long inseam (nearly 32"!), so I personally would have to go with the smaller bike in order to be comfortable. If it's not so ridiculous, you might find the 19" works for you. Can you test a 19" out? (I know it's not easy to find one...)
The FXes are nice bikes and should work well for what you want to do, provided they work for you. Plenty of people on here have or had one.



I'd also like to start doing some longer recreational rides on the weekends.
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