Basically it's hold the model vertically and have the wire horizontal to the mainplane with the lower attachment point leading. Thread the wire in using fine tweezers and rotate - your first contact point should be the upper mainplane adjacent to the middle of the cabane strut. Then once the wire is attached either let gravity take over or use a fine needle point to push the wire down into contact with the fuselage. Add a tiny drop of superglue to secure. Use slow setting superglue and add plenty of curses and swear words. One has to expect several attempts to get an attachment point but sometimes you get lucky and it goes right first time.

Even without the two rear wires the work is superb.

The mounted topwing looks great, Max @maxw
Always a pity to see those issues occur, but I'm sure you will get that solved with your skills.
Great start on the rigging as well.

Looks absolutely wonderful, my friend @maxw! It happens to face fit issues upon attaching the top wing on biplanes, however your excellent skills will easily remedy everything.
This is already a superlative model down to every detail!

Getting there! Still need to fix that interplane gap though.

2 attached images. Click to enlarge.

Looks excellent, Max @maxw
Would white glue be a solution.

Bit of tidying up to do but delighted that the rigging is substantially finished:

4 attached images. Click to enlarge.

Very good work on the rigging, Max @maxw