Moving WLM emails to Outlook 2016's .pst format

Hi - does anyone have experience of doing what the title says? Most of the articles I've read seem only to apply to Outlook 2013. Is it best to use a third party program and is so, can you recommend anything which has (or hasn't) worked? There are so many listed if I google the question.

Also, does anyone use Mailstore to back up their emails? If so, what happens if you want to restore a WLM once you've carried out the transfer?

Thanks.