1- you may marinate for up to 30 minutes, but I do not recommend marinating for any longer than that.
2- While I left the peels on for the photos, the shrimp are much easier to eat if you peel them before marinating & grilling.
After cooking through, shrimp may be stored in an air tight container in the fridge for up to 4 days (though they have the best flavor if eaten within 48 hours).
Heat in a frying pan or on the grill over medium heat until steaming hot. Do not reheat more than once.
If using wooden skewers, soak them in cold water 30 minutes prior to grilling to avoid them burning and breaking.
Use a long handled silicone brush to brush the maple syrup on the shrimp while grilling.