Just in case anyone else is wondering how to do this, here’s my little recipe!
– Duplicate layer
– Add “Blend” effect to duplicated layer
– Rename layers to know which is which
– Set “blend with” to the original layer in the fx controls for “blend” on the duplicated layer
– Add whichever effects you wish before the blend effect on the duplicated layer
– Use “blend with original” control to control dry/wet mix
– Voila!