I'm sure acceptability is dependant on where you are, so bear in mind that my advice here only relates to Scotland and Canada. Sadly, I am at an age when attending funerals is becoming more frequent, so I'll just tell you what I have been wearing for the past dozen years or so: charcoal grey, dark tweed and black jackets (no silver), always with a vest, a white shirt (never coloured), dark grey or black tie, and solid-colour hose (no tartan, no dicing and always black or charcoal-grey or charcoal-green), black flashes and black brogues.

I guess I'm fortunate in having a number of tartans in the closets to choose from, but my dear and so-observant wife tells me that the kilts I have been wearing most often to funerals over the last few years are a modern Davidson pleated to sett (that makes it pretty dark), Seaforth Mackenzie for the funerals of "Budge" Bell-Irving and Smokey Smith, Clan Chattan by Jamie Scarlett for the funeral of the late Mackintosh, and a muted Davidson woven by Dalgleish 35 years ago or more just last week.