I have never had much success with the Kynshot buffers in my Shrike.
I started off with the regular 5.56 Kynshot buffer and would get both short stroke issue as well as failure to strip rounds from the links. I ended up cutting the piston down and rewelding the piston to the "head" of the buffer to decrease its stroke as well as the pressure required to compress the buffer completely so the gun could reliably scoop up the next round in the tray. This seemed to eliminate the short stroke issue but I still had issues with rounds being stripped from the links completely.
I also bought the 9MM Kynshot, 308 Tubbs flat wire spring, and installed an A5 tube. With this setup I still had similar failure to strip rounds but not as bad as the 5.56 Kynshot probably due to the 9mm buffer weighing more.
I have also played with a Colt Hydraulic in an A2 stock and it slowed the rate down and stripped rounds from the links but lived a short life as the pin holding the buffer together cracked in a couple hundred rounds due to the sharp piston recoil of the Shrike.
My take is that the Kynshot buffers have a couple issues.
1. They don't have enough mass in the right place to reliably strip rounds from the links. The place where the spring engages the buffer is that disk on the front of the piston and when the buffer and carrier comes forward and hits the link that energy/mass on a normal buffer that would be used to strip the round from the link is instead absorbed by the rear body of the buffer collapsing/compressing on the piston.
The Shrikes design weakness is that they have very little over-travel on the bolt carrier group to get a running start at the round in the link and the distance and angle into the barrel is a pretty sharp transition. So you really need a sharp impact on the cartridge to dislodge it from the link and force it down and into the barrel. Due to the design of the kyshot buffer where the buffer spring only directly controls that little disk on the end of the piston, the buffer absorbs some of that impact energy on the forward feed stroke as most of the buffer mass is on the end of the little collapsing piston rod.
2. They absorb too much rearward stroke so you get no "bounce" of the buffer+carrier off the rear of the receiver buffer tube which helps with stripping rounds from links and they can also cause the gun to short stroke as well exacerbating the limited bolt over-travel issue inherent in all Shrikes.
3. The kynshot buffers also are not great at controlling bolt bounce as they have very little dead blow hammer effect compared to traditional sliding steel (or preferably) tungsten weights. Similar to the issue above, the only dead blow effect Kynshots have is the body of the buffer collapsing forward on the piston as the carrier slams home. I have a sliding anti-bounce weight inside my Shrike carrier to help with bolt bounce and without that installed all of the kynshot buffers I have will all experience bolt bounce with a dead downed hammer.
I personally both stretch and lube my links in order to ensure I don't get stoppages as I do like to shoot both US ammo as well as brass case foreign ammo (Wolf Gold, PPU) out of my gun and I also run a reduced power recoil spring to slow the ROF. I just have a pile of "shrike" links that have been pre-stretched over the years and hit them with silicone lube spray before linking them.
My personal setup that I have used for years is the MGI rate reducing buffer and a Springco Red enhanced spring. However, I have considered repairing the Colt Hydraulic with a better quality steel pin and also cutting it down to A5 spec (as the back end is just an open tube with extra oil in it) and trying it out again to see how it goes.
The challenge with trying to follow somebody else's buffer spring recipe is that there are so many variations on Shrikes over the years that different combination of barrels, gas port, gas regulators, feed trays, etc. all make folks guns behave differently. One gun may run great with a particular setup and another one will struggle. About the only setup that is close to a guarantee to run is the factory Ares spring, an H2/H3 buffer, and US made M855 belted into at least once fired links, but the cyclic rate is really high in that config which in turns help provide reliable feeding of rounds. Once you delve out of that prescribed combo all bets are off and its up to the owner to find what config their specific gun/barrel combo likes.