I understand your concerns but I searched on 4 Triumph forums for ignition switch and dip switch problems and found only one poster with a dip switch issue, where as there were loads of issues with the ignition switch - some with multi replacement.
Imo the brightness thing is down to the ign. switch being 'on the way out'. Before fitting the relay I did a quick test by taking a photo of headlights before the mod and then after laying a couple of direct feed wires from the battery to the lights, to be honest I couldn't make out any difference.
I think this has been mentioned by another poster and he thought that the dimmer lights were caused by extra resistance in the switch starting to go bad.
'Keep it simple' has always been my motto hence the decision to go the way I did - if it turns out it was the wrong direction I will come back on here and tell, my hips are broad and I can take the flack
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It will be interesting to see if the 2010 Roadsters that have had the wiring upgrade get any dip switch problems, also the 2011 models as well - this would be the 'proof of the pudding is in the eating' so to speak.