Yes I’m on about 25%, to be honest that’s for the point made about not using the small ring, more the hassle than the tiny loss of power/time (the micro-rest probably counters that anyway). I use most of the rear cog in that, most of it in the middle gears (though I have no fear of a little cross chaining either). I’m also light (62.5), but the 53/11 is plenty to push against there going downhill.
To answer the original question, I do all my training on Zwift as well as my limited Zwift racing (less limited this time of year). I never vary between racing and training. I don’t think it’s ‘wrong’ to, I just don’t.