The new Kernel [LK 2.07.beta1] allows you to backup the entire phone to a .TAR file. You can then use Odin to flash this file to the phone. You'll need at least 900 MB free on the SD to perform the backup.
Nope. It should be fine.
1.6 for the Spica? I don't think so! Are you sure it's the Spica? Is it possible that you've confused it with Samsung Galaxy (GT-I7500)? Spica is GT-I5700.
I did the following but the apps are still being installed on the phone memory...
1. Spica v.LK2.02
2. SamdroidMod v1.0.3 LK2.03.3
I have enabled Apps2SD through 'Samdroid Tools'.
Firmware - XXJCE