looking for a grilled fish recipe/marinade.

soy sauce, citrus zest, salt and pepper, old bay, forgot the evoo

Durkee citrus grill seasoning mix (from sams ). I either mix the citrus grill with italian dressing for a marinade or mix with oil for a rub. The chargriller is great to grill fish on, the castiron grates allow you to grill directly on the grates without a fishbasket and you can get a good sear.

whenever i cook swordfish or tuna I do the absolute bare minimum.
which usually is a 50:50 of sweet balsamic vinegar and evoo. I just coat the fish, leave it for about 30 mins and than cook. Can't see how this would change much for the smoker.
Both tuna and swordfish are fairly subtle flavours and great texture.

For Cold SMOKED salmon. I use a 50:50 coating of honey and balsamic vinegar - this would probably work for unsmoked oily fish as well.
basically the vinegar is there to cut through the fish's own oils and clean the palate. The evoo and honey are to help the vinegar stick to the fish and add a little sweetness.
You might be thinking 50:25:25. Balsamic:evoo:honey would be good.
But evoo and honey don't work for me together :-)

I'd use one or the other. And use it as the spritz/mop during smoking as well.