Installing Leopard the proper way

I have the leopard DVD since october but hadn't upgraded yet. I was and I am still waiting on Super Duper to be leopard compatible buy now it's only a questions of days (as of shirt pocket's blog). I'm then trying to decide which way is the safest to upgrade to leopard.

Upgrade is a no go as I have seen plenty of times with users having strange bugs.

Now I have to decide between either a clean install or archive and install. I'd rather have a clean install and import the apps I need back to the new leopard install from a backup.

Is it possible to run the migration assistant to pick up my stuff from Tiger from a bootable nackup done with Super Duper? Or should I use archive and install instead?

How much extra space does the archive and install needs?

I'm trying to sort out everything before taking the leap. I will also probably wait for 10.5.2 but I'd like to be ready to switch by then.

Thanks for your answers.