Hey,
I know exactly how you feel. I got banded in 2007 in a hospital that just started doing gastric bypass. In fact, I was the third person to get it done at that point. They sent me to a nutritionist and all that but noone knew what they were talking about so it was always a hit and miss with me. I was basically their guinee pig. I learned how to eat on my own, I learned how much Fluid was too much fluid, I learned that everyone is different and I learned that the nutritionist, unless she's been through it herself, doesn't have a clue. I lost 150 lbs in a year and a half, then I got pregnant, gained 100 and lost 70, then I got pregnant again, gained 40 and now I'm back to my original 150, which is the original 150 lbs I had originally lost.
How to know if your band is too tight -
If you can't drink Water and hydrate yourself, it's too tight.
If you can't go to bed without waking up in the night and needing to throw up cause the fluid in your throat is coming back up and not down, it's too tight.
If you can't eat small portions of meat, chicken, fish and boiled vegetables without puking, it's too tight.
Basically, ideally really, you shouldn't be throwing up. It can happen sometimes because hey, we're all human and we'll eat something we realize we can't eat but it shouldn't be happening regularly.
Everyone is different and can ingest different things. For me, I can do sausages, meat, anything on the bbq mainly, fish, boiled vegetables, broth (nothing thick), and anything i can chew.
Things that will for sure make you puke - burgers, hotdogs, sandwiches, pizza, things that you take big bites out of.
All in all, you should be able to eat but you shouldn't be able to scarf down food. If you can't even eat without puking, it's too tight. You can ask them to take out .5 or something, just to see. they'll adjust it until you are comfortable.
I hope this helps.