Hi, Knight7m. Thanks for your question.
I assume the most critical parts for sound in turntables are: Cart, tonearm, and phono preamp.
There are FOUR critical components in a vinyl front end: turntable, tonearm, phono stage and cartridge. The only one where you can (sometimes) get top class sound while staying on a low budget is the cartridge. The other three components are more critical... much more.
Having a high end cartridge is great. I use one too. But if the table, arm AND phono stage aren't of equal or better capability, you've put resources into a component that you'll never hear the full capabilities of.
This has been demonstrated many times, and is consistent with Linn's recommendations going back decades. When upgrading or allocating resources, look to the table, tonearm and phono stage first (in no particular order, each of them is vital). Look to the cartridge last (unless it's a known weakness of course).
Example from my systems, which include the following:
$8,000 LOMC, $200 MM
$6,000 TT, $500 TT
$5,000 arm, $500 arm
$12,000 preamp w phono, $800 preamp w phono
I've mixed and matched these in various combinations. Without any question, the worst sound is when I put the high end LOMC on the inexpensive TT/arm. The cartridge is so sensitive and revealing that it spotlights all the weaknesses of the rig supporting it.
OTOH, the inexpensive MM on the high end rig sings its heart out, playing way above itself because it's been given a top class support system that frees it to play its best.
There are few absolutes in audio but this one comes as close as any: a $500 cartridge on a $5,000 rig will play circles around a $5,000 cartridge on a $500 rig.
The difference between the two preamps is enormous. While the inexpensive one is no slouch (used c-j PV11, notably better than the Tube Box), the costlier one (Doshi Alaap) makes a staggering improvement. I've had critics and editors from audio mags visit my system. They only left after I promised to put them in touch with the maker of this amazing preamp, which at least two of them ended up buying for their own systems.
So, I agree with Jperry and Kiko65. You've put the cart before the horse by upgrading your cartridge well above the other 3 components in your vinyl front end. Time to start upgrading those. Until you do, you'll never hear what the Shelter can really do.
P.S. Don't get caught up in arbitrary categories like "Class A" or whatever other nonsense Stereophile puts out. Listen to as much as you can, talk to people with experience who seem to share your listening priorities, educate your own ears and judgement. You'll end up knowing a great deal more about what matters to you than any list in some magazine.