Current Tk::IDElayout and Tcl::pTk maintainer here. If one can get their program working with Tcl::pTk, I would probably prefer that approach over using Tk::IDElayout (which is somewhat neglected).

For the Tcl::pTk approach suggested here, using the $w->ttkPanedwindow() and $w->ttkStyleConfigure() methods should eliminate the need for Tcl syntax. Since Tcl::pTk does not include complete Perl/Tk-like syntax documentation for Ttk widgets, I suggest looking through upstream Tcl/Tk documentation and Tcl::pTk::Tile POD, and then Tcl::pTk's Ttk widget demos (e.g. ttkpane.pl) to see how it comes together.