We currently have a SharePoint 2007 farm and are migrating to SharePoint 2013 on premise + SharePoint Online hybrid. FYI we are using AvePoint DocAve for this.
We are trying to get as much contents as possible into SharePoint Online and only keep the highly complex sites (eg, sites with complex workflows, custom web parts, full-trust infopath forms, email-enabled libraries) in SharePoint 2013 on-premise.
So the requirement is to 'split' a site collection in the source and move a portion of it to SharePoint Online, and the complex portion to SharePoint 2013 On-premise. For sizing guidance, the site collection I'm looking at contains 400 subsites that is nested up to 4 levels deep.
Level 0 is the root site, Level 1 sites are the direct subsites of root site, Level 2 sites are direct subsites of Level 1 sites, and so on until Level 4 sites. We have conducted an analysis of these subsites individually and know whether they can go to SPO or there are complexities that dictate they have to live in the On-premise world.
So question here is what is the best and recommended way to split this site collection and push as many sites as possible to SPO.