No Panko breadcrumbs? Use any dried breadcrumbs, or make your own by toasting loaf bread(Tasty bread) slices in 300°F; for 10 - 12 minutes or until dried but not browned. Shred or pulse in food processor and use.
Once you dredge in breadcrumbs, make sure you pack the crumbs tight onto the shrimp to keep them from falling off during frying.
To devein or not to devein the shrimp? I usually devein large shrimps and prawns because I don't want to see the black intestinal tract when I eat them. That's just a personal preference. You don't have to do it if you are not bothered by it.
Pair your shrimp tempura with Vegetable Tempura since they use the same batter ingredients.