Splines cut with my newly made jig from last week
And top safely removed (even after I dropped a metal ruler inside when checking if I cut thru on the first side 🤦‍♀️).  Ended up pretty clean cut.  Did multiple passes and then left a bit on the short sides which I cut free by hand.  This is before any sanding (hard maple burned a bit). 

Happy with this afternoon's progress.  On to getting the splines glued in.