I have a question. Everywhere I've read about fishless cycling states that the bacteria need oxygen to survive, reproduce, and establish themselves. In a drystart, how is this oxygen being provided since there are no filters or agitation of the water? Or do the bacteria in a drystart not require oxygen?
Roots and diffusion.
For O2 to be gone/removed, the sediment to even become anoxic, anaerobic etc, you MUST have bacteria already established. Bacteria ARE what removes the O2, not plant roots(they pipe O2 from above, then floods sediments, there is a mountain/plenty of evidence of this), not simply a barrier, you have to have something to consume the O2.
100cm deep plain sand layer has the same O2 at the top as it does at bottom.
If you add organic matter, then bacteria, over time, will deplete to the O2, if it cannot be resupplied, then the O2 concentrations decline.
So careful not to put the cart before the horse
Anyway, if you wanted to say cycle the filter as well, not just the sediment, you could easily do this with a bucket, run the filter in there, add the NH3, say 1 Tablespoon and do it once a week for 4 weeks, that should be plenty. Then you dump the water later, no testing needed, no entire aquarium used to merely cycle a little filter.
Then fill the tank etc. The sediment is cycled, and established with a network of O2 pipes, called Roots........to support far larger populations, plants are loaded with bacteria, and they remove the NH4 directly, so you do not even need to bother with cycling the filter.
See silent cycle, this answers most of the questions regarding this part, roots/and establishment answers the other.
This is also why there's no need for heater cables or UGF's.