Hi Jim,
Seed balls seem like a useful technique to try, specifically if you have to subsoil in the dry season for logistical or practical reasons. in general, the keyline pattern cultivation is done just following the first significant rain event of the wet season. Hopefully this will generate germination conditions for the seeds spread during or just after planting.
as a technique for your specific site, you can try test plots of both and look at a
side by side comparison of success. I would also try a control test plot with no seeding done to see what the natural system sends your way from the memory banks.
cheers,
Neil