The recommended durood is the durood we recite in tashahud there is not issue of short and long and Rasul saw and Aummah they advised this one in salat
Aqeeq,firoza,Durre najaf and Hadeed are recommended
Mustahab in right hand in some riwayat one can wear in left if some one has no place in last two fingers of tight hand woman can wear in middle one also