Chunks
Eight loose items are hard to carry; three small groups are not. In Number Span split the number like a phone number, 7-3-9 / 1-4 / 8-2. In Light Trail group the panels in threes. In Flash Grid, take a big pattern as two or three small shapes rather than a scatter of squares.
Keep the groups the same size from run to run, so the split happens without thinking.
Names
Words are easier to repeat than pictures. The Light Trail panels have shapes you can name: circle, triangle, diamond, star, cross, drop. In Step Back with positions, call the squares top left, middle right and so on. In Flash Grid, a shape you can name (an L, a step, a diagonal) is one item instead of four.
Rhythm
The items arrive at a steady pace. Saying them silently in that same rhythm makes them easier to replay, and typing or tapping them back at an even pace avoids the classic slip on the last two items.
In Number Span backwards, keep your chunks and reverse them one at a time: the last chunk first, read from its end.
A moving window
Step Back works another way: you never hand the whole list back, you hold each new item against the one n places earlier. Keep a window of the last n items, push the new one in and let the oldest drop out each time. The pause between items is when that update happens.
Ladders as a measuring stick
Each ladder step is a fixed run with a target length, so a step you cleared yesterday is the same course today. That makes the ladders a fair way to see whether a new habit holds up.