One of the common issues causing problems with stitch length is cleaning; lint can gather around the feed dogs under the throat plate and hault the movement. A thorough cleaning and even scraping all grooves and corners with a tooth pick can be necessary. If theres lots of lint, you can be sure there's equal amounts under the bobbin case, it all needs to come out.
Another issue is oiling, pay particular attention to all links from stitch length lever to feed dogs; every thing needs oil, there is a groove you access behind the round plate in the back where the back of the stitch length lever moves up and down. There are quite a few joints, grooves and cam like parts involved. There is a tiny roller that can get stuck under the base, it often needs extra attention to start moving again.
Like Janey says, a 201 has full stitch length function forward and reverse, very accurate stitch length both ways when set. I know two people who have set up a 201 for free motion embroidery, one describe her technique as "like drawing with thread".
I don't know about "too tight in revese", but I guess it has to do with tension. You could do the drop test on the bobbin case (since it's a drop in bobbin case; a 1 oz. bag of rice or beans on the end of the thread). I am not a free motion expert at all, and I fuzz quite a bit to get tension correct for FM quilting; like you, tension is often on the tight side. It's all about getting it right. You should be able to turn the top tension dial all the way from 1 to 9, if not it needs adjustment. With a good thread and correct tension a 201 should behave very well.