Press firmly until glue is set. Some folks reinforce this area by adding a ply platform under the V but this has worked for me. Another approach is to make a moulded full-width saddle. Apply tape over the underside of the V and layup three or four layers of wing skinning glass cloth. Remove the newly moulded saddle from the tape and epoxy to the fuselage, trim to suit, and when dry fix the stab to the saddle using silicone rubber.
Stress cracks begin to appear after a while round hole for the wing locating peg .
Your mileage may vary. This photo shows egg-shell cracks which can appear on the fus after a while. Easily patched with lightweight glass cloth epoxied to the inside of the fus. No big deal, but it's worth watching out for particularly if you fly with ballast. You can try to bend it back with a hairdryer, but this could weaken the structure.