Having recently seen the pics of your tank, I believe the latter method will be just fine. The detritus that may get stirred up will be great food for the many coral. IMO, there will be no need for any external filtering because the coral will have totally cleared the water within an hour. (one year is actually a short amount of time for much detritus build up)
You know it's kinda sad that your request has received so few comments, even though it's had plenty of views.
Aloha,
Mark