Clevo -- your procedure might be fine if you know in advance exactly how many copies you are going to make. But what happens if, three weeks or a month or longer, later you decide you want to make a new set of copies. I am afraid I agree with gasgranny's approach in this.
I almost invariably take her approach with all my projects, though I produce a DVD folder because that is easier to preview than an ISO file, I find. The preview ability means I can go back and correct things if something is wrong -- rather like burning first to an RW disc: saves on wasting DVD blanks. But the idea is much the same.
However, gasgranny, I was struck by your comment:
I left it rendering last night before I went to bed so I don't know what the outcome is yet
This makes me think that it may be your workflow which is causing you grief. I get the impression that after you finish editing, you jump straight to the burning module (Share > Create Disc). The rendering then occurs as part of an already complex process, namely creating menus and burning. Various things can go wrong as it is highly demanding of computer resources, and of course the process can be extra long.
Instead, we recommend that, after editing, your first convert your project into a DVD compatible mpeg-2 file (Share > Create Video File > DVD). The conversion will still take a while, but doing this as a separate step places less demand on your computer resources.
Once you have your mpeg-2, save your project, and you then open a new one. Don't worry about a name for it -- the objective is just to clear the timeline.
Then you go to Share > Create Disc, insert your new mpeg-2 into the burning timeline, make your menu and burn. Also, make sure 'do not convert compliant mpeg files' is ticked in the middle of the three icons in the bottom left of the burning screen. You should not have to adjust any of the properties in the burn module. And no conversion (apart from your menus) will occur in this process. For a video the length of yours I would say that the whole process should not take much more than a half hour or 40 minutes.
Incidentally, for a 68 minute project, with a bitrate of 8000 kbps, but using Dolby or mpeg layer 2 audio, it should all just about fit on a single layer DVD.