Thankyou, I think its good to put the date so you can see how you where and how you can progress. I only started cross stitching when I was 18 and my first piece was for my nephew when he was born, it was a Me to You bear and murder to do!!! All grey and loads of tiny back stitch. And I've seen it since and its a bit of a mess compared to what I can do now. I've learned to stitch in the same direction throughout aswell coz it makes a big difference.
Yes, you should definitely always stitch in the same direction .... it's interesting that you are doing such large pieces ... it quite often takes people a lot longer than 5 years or less to pluck up enough courage to even start a large piece.
I have a floor standing frame which I absolutely love (bought it in the States) and it can hold any piece of any size. I also stitch with both hands - one in the back and the other in the front and get a lovely even tension with no distortion that way.