Bertie's multi-wholegrain sourdough: 

200g ripe sourdough starter (levain) @ 100% hydration 
550g sifted stoneground wheat flour
250g wholegrain stoneground flour of your choice or what you can find.
My choice for the 250g:
100g rye
100g ancient grains (khorasan/witwol)
50g Corn flour/mielieblom 
20g salt
My timeline:
12:00 feed your levain with mix of flours and equal weight water (e.g. 100g starter, 50g water, 50g flour)
18:00 Autolyze - mix the flour with 680g H20 (34 degrees Celcius) 
18:30 mix final dough - 200g levain, 20g salt
4-6 folds and then let it rise for an hour before going to fridge at around 22:00
06:00 take out of fridge, divide and shape, proof until ready
09:00 bake in dutch oven or on baking stone for 50mins at approx 230 degrees