Once Removed is by far one of the hardest concepts in challenge square dancing.

The 'step thru, do the call, step back' action is somewhat of a cheat, in the sense that it only works some of the time. In fact, if we had a Tidal Line in which each side had an Inverted Line (e.g., from Magic Columns after a Hinge), on the call "Once Removed Here Comes The Judge", if the dancers step thru then try to do the call, they are guaranteed to breakdown.

In other situations, it is impossible to take it out. For example, from R-H Columns, do a 1/2 Circulate then have the Very Ends do a U-Turn Back. Suppose the call is 'Once Removed Remake'. How do you take it out? It can't be done (easily) since the two formations share the same center of gravity.

Personally, I do not like the 'take it out and put it back' style of dancing. As a caller, I try only to call instances of concepts in which the dancers "can dance" the call. Whether or not the dancers can actually figure out how to dance the call is another matter.

I think the most important part about doing Once Removed is:

1. Determine who you are working with. Visually memorize the dancers in your Once Removed setup. This is important so that
   1. you know who you are working with (so you can work with them!); and
   2. you can do a sanity check after completing the call to make sure that the same dancers are in the resulting Once Removed ending formation.
2. Note which wall your group is closest to, so that at the end of the call, you can verify that everyone in your Once Removed group is closest to that wall. Of course, this doesn't apply when the center of gravity for the two Once Removed groups is the same.

Traffic-pattern-wise, different calls require different traffic patterns.

1. There's the 'step thru, do it, step to an opposite-handed setup' method that you mentioned above for Here Comes The Judge. I think you should show the dancers this style, but caution them that it only works when
   1. all the dancers in the Once Removed setup are facing the same direction; and when
   2. the call changes everyone's facing direction by 180 degrees.
   If the dancers blindly follow the 'step thru, do it, step to an opposited-handed setup' method, they will breakdown on many Once Removed calls (e.g., the Once Removed Here Comes The Judge from a Tidal Line consisting of Inverted Lines).
2. There's the 'take it out, do it, put it back' method, which works for calls such as (from Squared Set after Heads move into the middle) Once Removed Split Square Chain Thru. This method sometimes requires additional dancing skills to put back the Once-Removedness (e.g., from the same setup: Once Removed Split Square Chain The Top To A Wave. Take it out, do the call, Stretch it, then have the Centers of each side Slither). Many dancers call this 'Drag-and-Drop'.
3. There's the 'go to footprints for each part of the call' method, which only works for non-shapechangers. Example: from Starting DPT, Once Removed Touch 1/4 & Cross.
4. There's the 'twosome' method, in which dancers dance the call Twosome instead. Many dancers find Once Removed easier after learning Twosome, and I sometimes get requests from dancers to move Twosome to C2, and move Once Removed to C3A or C3B.
5. There's probably a few other methods, but I can't think of them right now.

My recommendations:

1. Teach your dancers to always determine who you are working with and note which wall your group is closest to. That is, memorize the dancers in your Once Removed setup, and memorize the 'heavy' wall.
2. Drill the dancers on calls using each of the above mentioned methods. Spend one session doing the 'step thru, do it, step to an opposite-handed setup' method, do another session on 'take it out, put it back', do another session on the 'go to footprints after each part' method, and finally, do a session on calls that can't be done using any of the methods taught so far (such as the Once Removed Remake mentioned above).

Ceder Chest Definition of Once Removed