Thanks for the help dude. I’m leaning towards keeping the Axis, using the 16gn insert, and putting 10gn iron will collars over. That will essentially keep my arrow weight exactly the same as it is now (+1 gn) and I can modify the new shafts so that they’re the same length as my current arrows so I can keep shooting those as well.I don't think there's anything wrong with stock Easton 16 gr aluminum HIT's. The strength of the HIT "system" comes more from the carbon shaft surrounding the HIT than from the HIT itself.
The HIT design is patented, and they're only made by Easton, Iron Will, and Ethics Archery. Easton offers 16 gr aluminum and 50/75 gr brass versions. IW and Ethics have stainless steel versions up to 100-150 gr. I would choose the cheapest option that got me closest to my desired total arrow weight.