Each 3section period is only ~105 minutes long plus admin time. If you can't hold it for two hours then that is what the diapers are for. TLS has some good breakdowns of styles to choose from.
if you can't be talked out of taking a PT this week ... either take it as a timed 3section or untimed as folks have said. this close to the test you don't need to be seeing a score, IMO.