A lydian tuned harp (aka Country Tuning) is a richter tuned harp with the 5 draw raised one half-step.
On a Lydian C harp, the 5 draw is a F# instead of a F. So if you’re reading a lydian tab but use a richter harp, replace 5 draw by 5 overblow.
If you’re reading a richter harp tab but use a lydian harp, replace 5 draw by 5 draw bent.