Well, I just got my Ericas strap.
Yes, it's very nice and comfy, and looks great on my Sinn.
But man is it a bear to latch the hook end onto the adjuster bar.
Takes me forever.
What's the secret to easily hooking it on?
Be patient, it gets easy very quickly. With the first one that I purchased I was a little frustrated at first and didn't understand what other's were saying about it being easy....
What works for me is I simultaneously, lightly apply a little upwards pressure to the buckle that receives the hook with my right thumb (watch is worn on my left wrist) I simply drop the hook into the buckle while also using my index finger to steady the hook and the far side (right side of the hook towards my hand vs my body) is stabilized with my middle finger. It becomes very intuitive and fast.
You should feel a little resistance as the hook catches the inner lip of the buckle and when you do, I apply a little downward pressure of the strap end of the hook away from the buckle towards my right or also gently apply a little upwards pressure of the buckle with your thumb. This is done with my thumb and middle finger. You may also use your index finger to stabilize the angle of the hook as the hook catches the buckle. This all sounds more complicated than it is ..... The hook catches the buckle and you're all set !
You'll quickly learn the "feel" of the correct angle as the hook initially catches the inner edge of the buckle and this is all done literally within just a second or two. I usually just use my thumb and middle finger to grasp the hook and don't need to use my index finger to stabilize the hook but it may help initially to use the index finger as well....
One method that I find makes things easier is to hook it on while the overall fit on the wrist is loose, and only then, once the hook is on, tighten the strap by sliding the hardware up toward the watch head.