Dear experts!

I am thinking of only shooting 16:9 HDV even if SD 4:3 is required as mostly today in Sweden for broadcast. But shooting everything in 16:9 HDV would mean that I will have a more futreproof archive of HDV material.
You can set the viewfinder with 4:3 marks on Canon XH-A1 using the aspect guide in the display setup - so it wouldn´t be difficult to see that what area you get in 4:3. Great!
I also understand it is possible to crop the 16:9 HDV material to 4:3 SD in say Final Cut.

Now I wonder if anybody has practical experience of doing this regularly?
How tricky is it?
What is the best process?
How much longer does it take to convert material in say a 15 min story?
How is the quality compared to shooting 4:3 directly?
What software have you used?
Is there a simpler way to do it with Canon XH-A1 already when capturing the material?

Thank you! Erik