Newbie here. I've been following this as things develop.
My gut feeling on this is that something really doesn't sit right with the whole case. I'd agree from the court reporting that we've heard that the prosecution appear to have a very strong case but i do not think for one minute that the circumstances surrounding this tragedy are in any way clean cut.
The home life of the accused appears chaotic. This in itself could be quite misleading. The various reporting of heavy drinking (both accused and his mother), smoking dope, the party, a seemingly relative normalisation of going to and from the house in the small hours, late showers etc etc has a kind of 'teenager-out-of-control' subtext to it and it would be very easy to make sweeping assumptions based on this, but this kind of behaviour generally isn't all too uncommon in the poorer parts of the west of Scotland (ie Inverclyde and Ayrshire coastal towns), and certainly not on the smaller islands and peninsula's where kids have very little to do.
I struggle to see pre-meditation in this, primarily because there appears to have been very little in terms of a 'plan'. I also struggle with the actual timeline itself. It is almost 'efficient' given the distances and terrain involved, and the fact that it would have beeen pitch dark (being on a rural peninsula there would be very little in the way of ambient lighting). It could be argued that efficiency and pre-meditation normally go hand-in-hand. If the intention was just to locate and steal drugs, but it became an opportunistic situation, then what is the catalyst for it suddenly turning into such a seemingly violent and sustained assault. The accused would have to almost have had some kind of episode or tunnel-vision *not* to realise what was going to unfold as a result of their actions.