"No more DIP" sounds more like "PLCC and other packaging will be available". This is also how I understood Thom.
And then you could go this way - either by incorporating the traces directly on your board or using it piggybacked:
This was mentioned on the Fujinet Discord yesterday as well.
@tschak909 wrote that only the DIP version is discontinued. Perhaps he will be summoned and elaborate here.
You don't need an external tool to generate a boot disk image.
A little bit of magic with MADS' assembler directives can generate an ATR diskimage directly from the assembly process.
If you like, I can support you there.
Then you have to do it your current way and forget about using a DOS because as Wrathchild just wrote: Loading something with/from DOS requires more or less to start at $2000.
To make it run on real hardware you need to create a boot medium which does not need any DOS but reads raw disk sectors or tape blocks.
The Atari's OS out of the box supports nearly any starting address and can load one continguous block of data by itself. In your case this would be $0600-$1FE6.
Does 8ko mean that your program has only 8KB or that you will use only 8KB of the machine, meaning addresses from $0000-$1FFF only?
This makes for a very big difference.