I'm not sure why you think torrent [or magnet] links circumvents the Forum rules here...
Anyway - on topic this is just an 11.3 ctrnand - alternatively you just downgrade the 6/7 titles [or how many it is] that were upgraded, right?
The only potential issue with updating to latest firmware is if you need immediate access to HBL as it takes few days for a new otherapp.bin payload to be made.
Yea if you think of it in terms of ROMs being full dd copies of a memory chip [64MB/128MB/256MB/1024MB/2048MB etc.] - and cias being the minimum required as they just get installed to a folder - it makes sense that gm9/d9wip auto-ignores the trailing white-space when converting to cia
4: duh - yes it is; .3dsx is for homebrew apps - roms are .3ds and when converted to .cia they should be automatically 'trimmed' there shouldn't be any 00'd space in cias afaik.
[Decrypt9 should do it]
The phrase 'how do you uninstall CFW' comes to mind or 'switching from rxtools to luma3ds' or 'something to do with GateWay'
Making people know the 'cfw' is that 1MB [or whatever it is] arm9loaderhax.bin file might mean we get more cerebral inquires than that.
Anyway with 'sighax' soon we...
For explanation sake though, it is useful to point out that luma3ds is a sig. patcher; meaning that the underlying firmware is still 100% stock [unless you deliberately alter system titles] - rather than being an actual fw itself.
Hbl will work if you tick the bottom box in luma settings -- but...
Just to quash the brick remark - to nrick you have to mess with the nand or mpre specifically the firms. So the second or two it takes to install a9lh is a brick point.
Outside of install guide - messing with gm9 can cause bricks, as does system updates - esp. without proper protections and...
Just format the new card to fat32 and copy files over.
Backups -- keep them somewhere if you can -- they'll save you if something messes up, but you don't need them on the sdcard
Edit. the hbl cia should work fine on 11.4
You could download 11.3 titles but I think it would be easier to update to 11.4; and then downgrading the updated titles -- if you feel the need for HBL