Thx for the feedback, arrangement is constantly being changed at the moment whilst, when I write music... well, it tends to write itself, constantly evolving (which is where the 2nd part is coming into it) but it could probably come in 4 bars or so sooner (at the point where the first electric guitar comes in) then there's more to do in terms of the drum work etc and making it more varied, at the moment it's there to drive the track whilst I work
Although it may depend on your mood as to how fast it should progress as well, if you're very chilled out, lights are down, then progresion can be slower as long as it constantly evolves and keeps you senses interested, I want parts to come/go and you not realise until it's actually playing something that wasn't there a few moments ago.
My music normally tends to be 2-3 minute pieces, short/punchy, into the beat/chorus quite soon, but with this i'm going for a 10 minute epic and thinking of scoring an entire OST for some fictional sci-fi/atmospheric movie