I would, as many mention, demo both ideally in the same, well treated room. Your ears are always the best judge. The best audition is each in your chain blind A/B tested but I realize that just is not possible most of the time.
Short of an audition, measurements are your next best friend. The Kef Blade Metas are one of, if not the best measuring passive speaker to date. Spinorama is a great resource for measurements. I do not see any Wilson speaker, including the Chronosonic XVX measuring better. Again measurements are not a substitute for your ears.
Do not trust anyone else’s opinion. Most opinions are owners defending their purchase decisions. Few have auditioned more than a handful of speakers. Professional reviewers do not want to alienate manufacturers and make a living by keeping buyers constantly in upgrade mode. Audio shops generally have relationships with particular brands so their obviously biased. My opinion and any others opinion is of absolutely no value to you. Spending this type of money it is well worth your effort to travel to a reputable shop to hear them.
Positioning of these speakers, or any for that matter, is critical to what you are going to hear. I live in a city with many fellow audiophiles, some with tremendous budgets. I can not tell you how many times I have listened to million plus dollar systems that sounded less than amazing simply because the owner thought dollars spent on equipment would some how absolve them of the painstaking work of careful arrangement of the equipment and furnishings of the room and treatment panels placed in positions that best support the sound at the listening position. Become an expert in this aspect and you will find that a modest system can easily out perform the TOTL system set up by someone who does not have the same experience.
My best advice. Find a well recommended acoustician to help you out. The advice from someone who knows what they are doing and has zero stake in what you buy is the best money you can spend.