Please re-read my post. It would not split the leave voters.
Voters would be able to vote for both leave options, one leave option or no leave option (that is, vote remain). I have set out one set of questions that would work. There are others. You could also use a single transferable vote. It would do much the same but I like the simplicity of actually voting for each option.
With respect to your comment that referenda shouldn't be routinely re-run, I tend to agree. Normally a referendum expresses a principle and Parliament works out the details. In this case, however, this system has failed (largely due to the ERG, if anyone is interested in apportioning blame). As the politicians seem to have no way forward, the only group left that is capable of making a decision in the electorate. Inconvenient, obviously, but the only viable option at the moment