I had same case, YW and SFA 兩間學校都收 one year ago. I had struggled one month, I already paid $3500 to SFA for the seat. Finally I choose Ying Wa.
Besides, I also need to have 1 hour travelling, so I moved to Lai Chi Kok this school year.
For your information, one of my son's classmate trasferred from SFA in P2 also.
The only concern to take YW is whether you have sufficient manpower to send him to-and-from school for ECA, as you must take one sports and one art, which is also very demanding in time. On the other hand, you are free to take any ECA at SFA.