F1+OPT teaching treaty

Thanks for the great answers to questions in my previous post.

I took a look at the treaty articles again. As I said in 2005 I was half time F1, and then half time on OPT teaching in a university. My income is fellowship plus res assistantship, and OPT wages.

Do I get to claim $5000 under article 20(c) only or can use the teaching (no limit for 3 years) under article 19?

Do I use 8833 (in addition to 1040R) as indicated in some old posts?

Thanks.