One way to see if the Keeper is really too small to fit into your vagina or if you're having problems with the fold "popping" open before you've got it in would be to fold it tightly and measure around it with a string. Then, if you can fit something that doesn't have a "pop" of that inside your vagina, the problem may be with holding the Keeper? (Maybe measure around the outside of the folded Instead with the string and see what the size difference is... it hasn't seemed that much of a difference to me, but I've never actually measured it.)

As far as Instead goes, I love them, but they are always messy (for me) to take out. It's because that when I "hook" my finger under to pull it out, it pushes all the blood up and over the edge. Also, it's got to become refolded to get back out, which pushes the blood over the edge (again, this is how it works for me, at least.) With the Keeper, once you manage to get it in, this mess won't be as bad (at least it won't be once you've gotten used to it, my experience was that I made a mess during the "getting a hang of it" phase!)