However well someone else puts together a cube, it will always be based on THEIR preferences, not yours. They might like their cubes looser than you, or with a different lube.
You might get lucky and get a cube from FastTech which is perfectly tensioned to your taste, but I'm finding more and more (as I become more of a cube snob!) that I like things my way, not someone else's. The last 3 pre-assembled cubes I've bought, I've had issues with - a Zhanchi that had spring noise on 2 faces and uneven tensions; a Fangshi that had spring noise on 1 face and uneven tensions (seriously, barely cut 15 degrees on most faces) and a MoYu which looks like it's been stickered by a blind person with no hands. So I strip the stickers off, disassemble, lube, reassemble, tension... by which stage it would have been far easier to buy a DIY.
Personally, I like my cubes tight. Someone like Feliks can get away with really loose tensions (he mentions this in one of his hardware vids) because he has a very accurate turning style. You can't go wrong with Cyoubix tutorial - it's sometimes really hard to tell if you've found the sweet spot, or if it's too tight, or too loose, but as I say - it's down to personal preference anyway. Don't feel that your cube has to be able to cut 45 - it's capable of doing it, but might not be beneficial or suit your style. If you're a rough turner, make it a bit tighter - not only will this stop pops, but it will improve your turning accuracy in the long run.
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