you may sit reserve at Shuttle, especially in ORD. Right now there is a good amount of movement on the FO lists on all three certificates, as there has been a lot of upgrading. Shuttle will be adding aircraft next year, so I am sure your reserve stint will turn into holding a decent line within 6 months. Again, it is all about the base... start asking about junior bases when you are in class, as every month the junior base changes.

The 170 is very similar to the 145 in terms of cockpit interface... similar enough that you might get the two confused. Try to learn the 170 as though it was a new airplane, and do not compare it to the 145 while you are in class. And in terms of flight characteristics, the controls on the 170 are lighter... it takes less pulling to get her off the ground, and you'll have to stop muscling the plane around. The plane weighs a little more, so it is a little less responsive. Still, you can toss her around when you need to, and she hand-flies nicely.