"How long is a piece of string?" I would suggest that this is the sort of question only you can answer. In my case it would depend on my fitness, the forecast weather conditions, the amount of snow cover, the type of equipment carried, my knowledge of the mountains to be climbed, time of day and probably several more items that I, subconsciously, consider after 50+ years on the hills.
Never take advice from others about whether YOU should be attempting a particular hill, unless they know YOUR abilities very very well. If you are not sure of your decision then you should probably not be going up.
No doubt someone else will be along shortly with the opposite view.
As the old saying goes "Everyone is entitled to my opinion!"

Pete's right, it's an entirely subjective decision based on past experience, present abilities and, often, how one feels psychologically on the day. I've taken a few chances on the weather in my time, some paying off handsomely and others making me curse for subjecting myself to some dreadful walking conditions. I would stress the mood element though. If you look at poor conditions and find yourself quailing at the thought of climbing into mist and possibly worse, then listen to your gut feeling and opt for low level. Much better safe... as the saying goes.

Colin

Its getting worse!!! some of these questions are getting silly, (if your not experienced enough don't go anywhere near them till you are,,,) flaming hell !!!!

Silly questions do not exist - actually, the choice of route question is something many Challengers will have asked themselves.
Yes, it is purely a personal decision, based on your own abilities.
I am with Colin that your mood is a key factor. Looking at the hills in the clouds, I have always said to myself: is it worth it, torrential rain, high winds and NO views?
Only once I have regretted the choice to stay low: when within an hour the clouds lifted and I had blue skies the rest of the day. Nevertheless I had a wonderful day walking through the glens.
I have never done high level routes in the first days of my challenges, and many in the second week. Not only the weather conditions made me decide to stay low, I also need time to get used to the backpacking, to learn to read the Scottish weather again (I lose this ability in the Netherlands), and to get into the mood. That's why I agree with Cameron McNeish that it would be much nicer to walk east to west: when I reach the west coast mountains, I am broken in.
Anyway, these are my reflections on a not so silly question....

Thanks Bart and the others — appreciate it. Am well aware these are personal decisions and I have some experience with elevation in Scotland, although not being from there I have less than others. We’re all making these decisions and there’s different factors we’re taking into account. Was just curious how others who’ve done TGOC make these calls.