Here's some Reaper scripts to change RT/RD Sw <> Ev
Right click Save Link\Target As
Change selected audio item from swing to even.lua
Change selected audio item from even to swing.lua

These ones will do a section of bars only
Right click Save Target/Link As
Change selected audio item selection from swing to even.lua
Change selected audio item selection from even to swing.lua

This one will change the swing amount
Right click Save Link\Target As
Change selected audio item swing amount.lua

Even Jazz demo with Swing Sax test
Watch Video:
https://www.dropbox.com/s/u2dxrzugzc60la2/Ev-Jazz-and-Sw-Track-Sax.mp4?dl=0
remove .mp4 from zip below