Yep, I was using Gold Tip Pierce Platinum.
I'm not saying I'll never use them again, but there's only two reasons I can think of to use a 4mm shaft: Wind Drift, and Penetration. Both theoretical advantages, but I'm not sure how much they matter in practice, especially penetration. Wind drift could on longer shots in open country. The disadvantages are reduced durability, limited broadhead selection with deep 6, outserts harder to get to spin true and can get damaged/crooked from repeated use in some targets.
All about tradeoffs... If I use them again, It would be with the setup I did this year, but with a broadhead like a Deep 6 Iron Will. But, by the time you're done with them, there's a lot of time and $$$ into each arrow.
I have been beating my head against the wall on this one. Basically, I agree with you and Beendare. It is a whole lot of trouble dealing with a 4mm shaft. D6 is out as far as I am concerned the shank of the broadhead is too small.
The only reason I keep revisiting the micro shaft is for one specific hunt I have this year where I will be in the mountains with wind, steep cuts and the most difficult conditions for a bowhunter. Personally, the penetration claims are un-warranted, I passed through a Bison 20 years ago with a 2216. You don't need micro-sized arrow to do that.
BUT the wind is a real thing, my real world testing side by side with an Axis shaft is 4-6 inches of wind drift at 100 yards. That is substantial enough to consider.
At this point my plan is to build some VAPs with the 95 grain insert/outsert. And just soot them compared to the Axis and Injexion W/outserts. Whatever shoots best will win.