I teach at a retirement community and we have a number of direct tie-up looms. My beginners often have trouble remembering to alternate their feet on treadles 1&3 and then with 2&4. To make their experience a positive one on early warps, I thread the loom 4-2-3-1 instead of 4-3-2-1. Then I make a bridge of cardboard top and bottom between treadles 1 and 2 and tape it in place, likewise with treadles 3 and 4. Now we have a loom with two treadles for plain weave. Then I set it up so that when the shuttle is on the left, the left foot steps on the left treadle, weave through, beat. Then the shuttle is on the right, so the right foot steps on the right treadle and so on.
The threading creates plain weave on 1&2 against 3&4, like the early weavers did on counterbalanced looms, to pull the two front harness against the back two. On modern looms this threading and combining of treadles accomodates memory problems and wide shoes!