Hi Carl thanks for posting in the Lucid community - I'm happy to help! Unfortunately a "Match Size" function for swim lanes isn't currently supported in Lucidchart. However I certainly understand how this would be useful and impactful to your workflow. If you're willing to share our development team would be grateful for your feedback and use case details via this feature request form. Ideas submitted here are considered when prioritizing improvements to Lucidchart. In the meantime as a workaround you might find it useful to enable Rulers to ensure equal distance which you can do by selecting View > Show Rulers.

Thanks for your request and apologies for any inconvenience!