I think sardo went away because it got a bad reputation.
Part of that reputation is unfair imo... part of how the rack works is you intentionally put some dents in the cloth in the racking area. So people thought "oh, so this whole clamp thing is a fake gimmick, what's really giving a tight rack is the dents in the cloth." ... they also thought "I don't want those nasty dents ruining the natural roll of the ball and causing problems when my cue ball stops there".
But I've heard people swear by the thin plastic templates used in the eurotour where they pre-tap all the balls into place. I won't say I've never seen a ball get caught in a dent but it's pretty rare, the dent has to be deep and the ball has to catch it just right, it's like 1 in a million. The tradeoff for that is that the balls settle into place completely frozen, without you having to fight for it. You can finish racking fast and they break great.
We've all occasionally tapped a troublemaker ball into place before, right? And a little known fact is that even if you refuse to tap anything, a dent will always form at the foot spot. The slightly airborne cue ball hammers the 1 ball down into the cloth on every break, so that eventually the foot spot develops a dent and even wears a hole through the paper spot. Since that dent is inevitable, I wonder sometimes if a few more can't hurt.
I think the delta-13 is the best route if you refuse to tap balls into place. Wood and plastic racks can have the sides weakened from people pushing the balls upwards into them. Eventually the weakened sides bulge out a bit and can't form a perfect triangle anymore. The two balls behind the head ball especially refuse to touch each other. You'll find that these racks have to be rotated once or twice to find an alignment where the bulge isn't screwing things up. Some racks have no correct alignment, they're that deformed. The delta solves the problem with common sense... it's metal, it takes a hell of a lot of pushing to deform the side.