Poeple have done various things in terms of the angle but if you look at the guys who pioneered this approach, Booth, Bundock etc, they run across a 90% angle. We went this way too at the same time and it worked fine - to be honest we hardly ever adjusted which loop we were using. You can argue about what is theoretically better but the Aussie idea was to make things as simple as poss - they used the sheet tension to achieve any twist required.

sm