Thanks for all the replies guys. Yes, I realise tapering would be the most technically perfect solution but I cannot see that it would make a significant difference for this scale of aircraft.

Yes, it might be slightly better but how much better? I think it would be barely noticable.

With regards the tail feathers thickness. It may sound thin in comparison to the wing and thus there could be flexing. However, this is the what the plans call for (and have been tested) and the tail pieces I've made are solid balsa, with cross laminated sheets. This is really strong. I tried this technique on a trainer when I snapped the tail off after a tumble in high wind. The replacement parts were at least 300% stronger than the original "built up" construction with a barely noticable weight penalty that I couldn't detect in the air.

I will try to taper off the TE a little better but I'm not going to go overboard with it. Will be interesting to compare this to a similar model a friend is building, he wants foam surfaces with balsa sheeting which will be near impossible to get as thin as what I have already built.