Master Tam & Judy Hong’s group is currently working on this loooong form (takes over 20 minutes to complete). Try it, you’ll like it.
This form is slower than any other form I’ve met. This gives you time to think about and perfect your moves. Also very relaxing once you’ve learned it. Music with clear calls saves you from the effort of trying to remember all the moves in the right order.
The 4-corners move (like many) is tricky. At first you’ll need some extra steps for balance. Later you’ll eliminate those steps as you anticipate turns and can use your waist to turn as you rock (without twisting knees). But at first, there are lots and lots of little parts to remember. Here’s a very detailed breakdown of 4-corners that I found very helpful, even though I’ve already stopped doing some of the smaller adjustments.