A few ideas..........
I buggered up the rudder position, I placed the vertical fin too far forward by about 3mm and the 5 min epoxy had dried before I realised. Unfortunately this left about a 2mm gap between the fin and rudder, which I sealed with tape at this stage, to prevent flutter.
Whenever you have a situation like this again, where you've placed the fin "out of reach" by the rudder, if the rear of the fin is square, just glue a strip of balsa to it to fill the gap. A strip of Ultracote to match the fin colors is easy to iron on for fuel proofing. Then hinge the rudder on and you're good to go.
If you've used the CA hinges, and got a 2mm gap, the hinging is going to be somewhat vague, even if you've sealed the air gap. It might be worth fixing the gap. CA hinges rely on being supported by wood everywhere except their bend-line. Truth is, your fix will fly but would be better fixed. And btw, sealing big hinge gaps does more than prevent flutter and isn't really done for flutter most times. And with a loose hinge like unsupported CA hinges would give, that'd contribute way more to flutter than sealing the hinge line would do.
Will your fix work? Probably. It's probably "good enough". Our models will fly with all manner of things done to them.
2-15/16" to 3 1/2" Can someone PLEASE convert the measurements to millimetres.
25.4mm = 1" so.........
2.94 X 25.4 = 75mm
3.5 X 25.4 = 89mm