the important note in the stupid meal is it says there are only four KNOWN arkentools, it most clearly to me has a caveat, it may be there are more than four but only four are commonly known of,

As for Parson, bank shot and win, personally as there are only so many fliers theyd have to be spread awfully thin or offer onesided protection on the column (protecting some siege but not all) its clear that this time he hits the siege again, maybe stays for a little more damage dealing then scrams all his forces back to GK as the closer Ansom gets, the easier it becomes to hit and run to GK and without siege GK should be quite quite safe,

if the air support was strung out to protect the siege id be tempted as parson to hit and run THE AIR UNITS taking them apart a few at a time piecemeal and stripping away another asset for the big battle