I agree with the above. I don't have a Primo Solid, so I can't speak on that, but the Xeno is an amazing ball. Definitely the earliest and smoothest of the 3, and I'd say handles the most oil as well - or at least similar to the Guru Limited.
My Xeno and Limited are drilled similarly with the pin beside the ring finger (maybe an inch or two off). The MB is below the thumb. I have a P4 on the Xeno and a P3 on the Limited. The Xeno is great on the fresh. It is not super early, but more midlane, with a nice smooth motion. Very continuous though. The Limited gets down longer and comes strong, but isn't quite skid/snap.
I went with a motion hole on the Ridiculous Pearl and that ball gets down nice and comes screaming back off the friction. It does not handle oil nearly as well as the other two. Pin is beside the ring on that as well, since my PAP is now over 5".
I also have a Guru Supreme drilled pretty much the same as the Limited that is similar in motion to the Xeno, but probably handles a little more oil. I'm basically saving that for the longer/heavier volume patterns. And I have a Jackpot which is 3" to PAP. Good benchmark on medium patterns.