Firstly you need to accept that you can’t always get what you want when covering up a piece, you will obviously need to work with what is there and try to get the best job you can from what is possible. I can’t actually see what you have as I can’t open the pic but best bet is to have a word with your guy and see what he feels confident will work well.
Only advice really is to stay away from guys who say tribal is the best cover up style and have a good think about if you will prefer the new work to what is existing already, last thing you want is to try and cover up a cover of a cover up.
Good luck.