Yes it's ok. But it's mostly for people who know how to pronounce catalan spelling.
But the worldwide use of Dima is also ok, his babushka probably calls him Dima.
Let's see what the catalan press will call him, probably Txigo, and then go with that.
Txigo for me sounds like Cigo and that is close to Cigan ( sometimes it's a short abbreviation for it actually ) which means Gypsy in some slavic languages so I'd say Dimi is better.