B) I built a fillet table in my back yard and have never had an issue with the bugs......but if I did I would go to the sporting goods shop and buy a canopy (easy up) made of mesh. they cost around $50 - $75 in the U.S.depending on how big and quality. They normally don't have a floor like a tent so you could stake the bottoms down in case its windy, and not worry about spilling guts and stuff on the floor. Just put a small table inside you can fillet on and bring your fish in when your ready. You'll have very few flies. I usually have a hole in the table and have a plastic trash can for the guts so we can use them as fertilizer in the garden.You can even run a water hose over the table to help
move the leftover parts and guts (mine is placed over concrete so it drains well). Even a small tent could do the job but you would have to sit while working and find a way to remove the floor for obvious reasons. hope this helps you My friend!!!