I actually do report at 60 mins, but invariably find that my F.O. has been there for at least 15 minutes and has already got the paperwork ready - so I suppose I cheat a bit.
If the pre-flight requires extra time then so be it and I annotate the Journey Log accordingly. The trouble then come with the requirement to be at the a/c 35 mins before the STD, or we get reported by the handling agents for being late - tough. Again on the Journey Log. It takes at least 15 minutes to walk to the a/c and on the remote stands even longer.
We do get an extra 15 minutes for early Line Training days though.
My attitude is that a proper briefing and safety over-ride everything else - that said we get away on time unless there is a problem on the day - lo vis procs, pax problems, security checks on pax etc.