Tail feathers

Having now bought my first low winger a seagul challenger I need help to fit the tail feathers It has been many year since I last tried and now mark one eyeball not good enough ! Would appreciate advise on how to set up model to fit them . And pitfalls to look out for !
Look forward to receiving helpful suggestions.
Thanks John P

Find a big table and with the wing bolted to the fuselage:

1. put equal height blocks under each wingtip
2. pin the tail in place and measure that each tail-tip is the same height from the table
3. sand or shim the tail seat if necessary
4. measure the distance from wingtip to tail tip on both sides (these should be equal but it assumes both wings are the same length and both tails too)
5. recheck everything before gluing in place
6. glue fin vertically compared to the tail

I personally find that the eyeball comes in real handy between steps 3 and 4 and just before gluing. But if your peepers are no good anymore you will have to leave out these steps.

Also before step 4 you should check wingtip to fin post both sides, no good having wing and tail parallel if neither is square to the fuselage centreline!