C.,
When my 3 kids went through that stage, I put large garbage bags under the chair, vinal tablecloth on the table, took off their clothes, turned up the heat (in winter) and just let them feed themselves. I also learned not to watch because it was hard not to react when they were messy. (I just knew it would be cleaner if I took the spoon away.) I endured it for a couple of months and they got good enough at it that we could go back to normal eating. I will say that if they start throwing food or shampooing their hair with it, they are no longer hungry and need to be removed from the table.
Also, look for foods that stick to the spoon (like oatmeal, mashed potatoes or foods mixed with baby cereal.) My youngest is 18 months and I still drain his chicken noodle soup. He gets the noodles with a spoon in a bowl and the broth in a cup. He also did better with a fork before trying the spoon. (You can find plastic ones with dull points in the baby section of the store.) My kids also prefer a booster seat on a regular chair over a highchair by age 1. (It gets younger with each kid because they don't want to be different from everyone else.)
No where is it written that you HAVE to feed them baby food. At this age, your baby could easily just eat soft table foods.
Best of luck,
S.