Congrats on the new boat. I would not recommend using duct tape. I'm sure  it 
would withstand the winds, but tape leaves a sticky residue behind which will 
 attract dirt and be hard to remove. If you can't drop the mast, The cable 
ties  sound like a good option. I would wrap a rag or towel around the furled 
sail  first to prevent any chafing. Dropping the IMF mast is a three person job 
(and  one six pack) and not hard. I can give you an in depth description of 
how I do  it if you want.
The sun shade on the main can be a little more work. You don't want to  
loosen the furling line, but you still want to be able to wrap it around the  mast 
and again tie it off with cable ties and a towel or rag.
If you do decide to drop the mast, remember to keep the furling  tube for the 
genny supported along it's full length, or you will end up  with a bow in it 
that will make furling a real unbalanced job.
Remember, in a high wind, the cable ties might have a tendency to walk,  
depending on how much is allowed to flop around in the wind.
 
Rummy