Normally what I would buy for that amount of area is 1qt of base, 1qt of clear. Now the mix ratio for the paint I use is base- 1:1 & clear 4:1 I use PPG What you want to get is plenty. The extra should keep. Make sure it doesn't freeze & you will have mix it really well when you spray the base again. The metallic will settle to the bottom. Just remember when it comes to paint material you get what you pay for. I never sprayed TCP global paint before so I have no idea how the base covers. I would say either one will be fine. Spray what you want & then see how much is left. Then you will know if you need more or not. Spray at least 4 coats of base & make the last one a mist coat with a little more air pressure & the gun further away. This helps the metallic to lay down right.