Duo2 upgrading image the easy way but is it OK for my setup

Have asked this question elsewhere but haven't received a reply so I will try my luck here.
My Duo2 is using BH 2.1.0 and all is perfect except for Hbb Tv and Blind Scan as I suspect there is bugs in this image (2.1.0) that effect these two so I'm thinking of updating to BH 2.1.3 but I'm scared of all the work I would have to do although I have backed up everything via Dreambox edit and Dreamset + backed up my LCD4.config file.
My duo2 controls 12 dishes + Terrestrial TV (using 3 tuners) + Cccam and in my setup I am using the complicated Advanced setting found in Reception settings for all my Satellite needs (using DISEqC 1.1 and 1.2).

Now for the 6 questions I would like you more experienced guys with the Duo 2 to answer for me.

1/ If I do a backup via Menu > Setup > Software Management > Backup System settings on my Duo 2 and I reflashed the duo2 with NEW Version image BH 2.1.3 and restored all back via Menu > Setup > Software Management > Restore System Settings will the duo 2 be the same as before I flashed it (all my settings,Sats,DISEqc,etc Softcams and other). Remember my duo2 is set up to control a large collection of Dishes via DISEqC 1.2 and DISEqc 1.1 + Terrestrial Local TV.
2/ Backing up via Menu > Setup > Software Management > Backup System Settings does not ask you where you would like to back up all you settings "eg" USB or HDD ....where does it back up too? HDD or USB?. (PS in Advance method of backing up you choose where you want to back up your files.
3/ Before flashing with new image do I need to disconnect HDD (for Sat and Terrestrial TV recordings) and also the rear USB used for Picons only.
4/ After box is flashed with new image and say I reconnect the HDD and USB, remember the Existing Hard drive has recordings on it and so does the USB as that has plenty of picons in it what do I do to get the both to reconnect with the new image. (DO NOT WANT TO REFORMAT THEM AGAIN don't we) Do I just do a re-map or Mount (forgotten which one formats which I don't want) or whatever so BH 2.1.3 will recognize both my devices.
5/ Any other matters I should remember/ do/ don't do before taking on this project of upgrading an image by backing up and restoring method.
Thanks
6/ Finally months ago whilst playing around I accidentally backup my settings via Menu > Set up > Software Management > Back up System Settings but this backup is stale so if I re -backup 5 minute before I'm replacing the image will the new back up overwrite the stale backup which has less settings and Dishes in it. (ps can I use FTP to Delete it in What folder?)

Yes I understand that after flashing I will have to do the basic things first like Language, Timezones, and other initial stuff when you first start the box after re flashing

Thanks for your reply.
Here in Australia Hbb is only new (months since it started) and have been told they are using I think if I'm correct V 1.15 whilst the rest of the world is using an older version. What use to happen was you would start Hbb TV and it would crash.
As for the Blind scan function. Blind scan works perfect for me as long an in your setup for LNB you use 09750 10600 11600 settings instead of 10700 (my lnb is 10700) but once you use the LNB settings 09750 10600 11600 then manual and Auto search become inoperative. All my other Satellite boxes I set the local as 10700 for a 10700 LNBF.

Nothing worse than doing something for the first time as once you do it and you succeed the next time you can breath a little easier. Trust me it took a while to set my box up the way its set up now and if I can back up all, change image, and restore it and say only minor things I would have to re-install or FTP across I will be happy.