For anyone who knows that just one Festool MFT workbench is not enough, here is a dedicated accessory to join two workbenches together! Base model is 200mm, so can either be printed in multiples or scaled in Y as needed to cover the desired length for your project

Based on the QuickMount Workbench Extender from Magmabow, this should sit flush with the top of the workbench and sets the two workbenches 88mm apart, which should maintain the 96mm hole spacing across both surfaces when set up laterally.