Petzl Irvis Hybrids - experiences?

So I’ve got myself a shiny new pair of Irvis Hybrids. Does anybody have any dos and don’ts with these things? I strapped them onto my Trango Extremes with the leverlock. They seemed relatively solid, but with just a bit of boot flex I could imagine them popping off. I’ve heard about the flexlock popping off boots, but that’s a little counter intuitive in the crampon world.

It would be great to know what boots people have had success with (or lack thereof).

I've only used the Irvis Hybrid with ski boots, so I can't really say how they do with boot flex, but I've been impressed with how solid they are. My first day on them I couldn't imagine needing crampons, but I threw them in the pack just to be safe having never sized them or put them on by boots. They were easy enough to size in the field, and they did fine for around 800' of front pointing even with the poor sizing on some Scarpa F1s. I've mostly been using them with the strap on toe on a pair of Hojis, and with a proper fit they do really well. I've been on class 4 rock with them with no noticeable play.

It worked pretty well for me to size them as tight as I could, leave them on the boots overnight, and then see if I could tighten them any more the next day to get the best fit. When I first put them on they look too small, but as I engage the heel lever it pulls the heel piece into place for a solid fit. The Dyneema crossbar makes them a little tricky to get into if you're in an awkward spot, but it's not too bad with some practice. 

This is a pretty rad crampon and was Ueli Steck's go to crampon for a lot of the stuff he did. A couple notes on the crampons that I've found

Use the "optional adjustment" method on page 6 in the Tech Notice for the crampons. It'll help you get a tighter and more solid fit to your boot.  

I second Will's notion of leaving them on your boots overnight and then tightening them more the next day. This will also give you a much better fit.

I have a pair of Leopards that I've used with Trango Techs and at first I was a bit concerned about the flex in both the crampons and the boots.  I don't know if the semi auto Irvis Hybrids have an alternative lacing strategy that works like the Leopards but wrapping the ankle strap through the center "bar" strand and then back up tensions the center "bar" and keeps everything much more stable.  

As an update for anybody interested in these:

This weekend I tested these crampons on relatively high angle ice (~80 degrees).  They worked considerably better than expected, in fact, I was so surprised that I actually laughed out loud! The symmetrical geometry of the crampons is less than ideal.  My belayer mentioned that she could see them flexing pretty dramatically under my boot which is a little concerning with the leverlock bindings.  I wouldn't bring them out planning to climb ice, but I wouldn't be afraid to do it again!

I know multiple people who have had significant issues with those popping off their boots.  It seems that the more flexible the boot, the harder it is to keep them on.

Nick Sweeney wrote: I know multiple people who have had significant issues with those popping off their boots.  It seems that the more flexible the boot, the harder it is to keep them on.

One thing I noticed as well was that after I initially adjusted them they seemed to loosen up quite a bit after being on the boot for a minute.  I popped them off and was able to take them in an additional notch.