On right angle joints I usually cut a strip, maybe 3/4" wide, and lay that in the corner before I do the larger surface. You need a trim iron to stick the strip tight into the corner. Also remember the general rule of covering, that forward pieces overlap after pieces, and pieces closer to the fuselage overlap pieces further out. This helps keep the airstream from driving exhaust residue under the seam.

As to removing control surfaces, I've done it both ways, depending on my thoughts as to the feasibility of re-hinging. If I re-hinge, I would more likely choose Robart hinge points if there's thick enough wood to drill into, or pin-type hinges--Dubro, GP, Klett, etc. if the surfaces are only 1/4" thick. I like the Dubro hinging tool, the sharp fork followed by the pick, since it makes you work slow and feel your way through the job.