Mousses anyone?
I much prefer them they just give you that ultimate peace of mind and you can stop worrying.
On tubes I've tried standard and heavy duty in the past and the only thing I'd say with HD which would worry me using UHD is that when you run low pressure, especially in a large carcass tyre such as trials the tube can spin. I had this happen and as the only thing holding the tube is the valve at low pressure it stripped a long piece of tube with valve attached off. The heavier the tube the more likely to do this. When it happened to me I was running 5-6 psi in a very muddy wet event. I checked the tyre after and it had not moved on the rim. The tube had ripped the valve out under braking judging from the direction it ripped out from. I deduced this was from suddenly having the rear lock under braking from 30 - 40 mph. The rear wheel stopping dead like that with a HD tube at 5 - 6 psi just tore the valve out eventually.
However .. if you are riding at high pressure, in the dry probably irrelevent. But I now use mousses in competition, live with the lack of grip in wet mud but have stopped worrying about punctures. Still use tubes trail riding sometimes but I get very few compression punctures so use standard tubes. I might be mistaken but I think something that penetrates the tyre isn't going to stop for the softer rubber of a tube, even a HD or UHD.
But it really depends on your terrain and style.