Guillaume,
Stick with #1) Raise 8,000.... Total 8,000. This is what the TDA wants.
#2) Is too much like a "string" Raise. If you said "Raise 8,000 more" or "Raise... make it 10,000" in my opinion that would be acceptable. In order to understand what a string bet, or string raise is, you need to focus on avoiding two separate actions, verbal or otherwise. You can't say: "Here's your 2,000 and I'll Raise you 8,000 more." Players will always look to your original 2,000 as the accepted bet.
#3) In my opinion saying "Raise, plus 8,000!" could go either way.
#4) Another "string raise," you would most likely be held to a 2,000 call. Saying "your 2,000 plus 8,000 is looked at as two separate actions.
I realize this must be quite confusing but try to focus on the proper methods for raising and you'll have a better understanding of what is acceptable universally. Either announce the total amount of your bet and raise, or push the "total" desired amount forward in one motion. Example: Player bets 2,000 next Player says "raise" 10,000...that will be the total bet+raise amount, (per TDA Rules) Or; Player bets 2,000 next Player pushes 10,000 forward in one motion.
Others will have comments, I'm sure, so you can wait for their replies or send Mike Bishop a personal message and maybe he can better explain this to you, one on one.
I'm adding this after noticing #5. I guess saying Plus 8,000 would at least guarantee a raise to a total of 8,000. I don't remember hearing the word "Plus" used the way you are using it, but this is where my initial argument comes from. By definition "Plus" means in addition to...so saying "plus" could cause confusion. Hope you understand what I'm saying.
