Difficult to answer as I don’t know what you need such a long list for. Is there no way to produce just a sub-set of the data? Perhaps create different variants of the TYPE, like “Common ancestor – group1”, “Common ancestor – group2” etc.
I don’t think kiwitrees is really the right tool though. If you are looking for bulk output of large amounts of data you need to be working on a local machine, not a web server.