During my internet searches I found the following guidelines:
The amount of starter used is best from a minimum of 15% but can be up to 40% of the planned total weight of the dough. 25% is reckoned to be commonly successful.
The less starter used, the longer the proving times; higher amounts should require less proving time. But of course this depends on other factors as well, such as temperature and ingredients. Taste will be affected by the length of proving time. Longer times produce sourer bread.
100% hydrated starter or levain is 1:1, e.g. 100g flour to 100g water. For example, my starter is 100% hydrated. If I use 200g starter I know I’m putting in 100g flour and 100g water when I add this to my levain or bread dough.
If you want to use the Baker’s Percentage for yeasted bread, the yeast content would be 1%.
Always use metric weights not measures like cups.
1 sachet of dried yeast is approximately equivalent to 1 cup of starter (mine weighs in at 106g a cup, give or take a smidgeon). This means I know I’m putting 53g flour and 53g water when I add a cupful to my levain or bread dough.
Levain is a pre-fermentation stage that can be left out if your schedule requires. Allow your starter to bubble a bit longer than normal after refreshing it, and prove the dough a bit longer before shaping. I have found it helpful to autolysed my flour by mixing flour and water (no kneading yet) and leaving these in a covered bowl in a warm place for 30 minutes before adding starter, and salt and kneading. This can also be left out if the timing is difficult.
Kneading by hand takes 10- 15 minutes. Use a stand mixer such as a Kenwood Chef if this is not physically possible, and of course assuming you have one of these. I find kneading is really good exercise for arthritic thumbs, but too often and over-long makes them hurt.
I’ve not tried a Magimix food processor, but I guess that would work as well the stand mixer.