I'm not an expert, but I've been playing around with different types of wheats and mixing them into my sourdough breads. I have inconsistently been trying things (and feeding my starter poorly), so I can't say anything for certain. But I have been trying to add ww flour in different percentages to see what works best.
A ww loaf won't rise as much as an AP flour one will, because all the little bran particles will slice through the rising dough. I have tried sifting the flour but didn't see much different yet. I plan to get a finer sifter to pull out the larger bran particles and either re grind or just discard them.
I would look into buying some
hard white wheat to play with. They say it has a milder flavor. My inconsistent loaves means I can't say if I found that true or not. I can say my einkorn wheat has a stronger flavor.
So, to sum up, try a milder wheat. And look into getting a
sifter (I have the 30, but plan to get the 40). Add small amounts of fresh ground wheat at first, and build up from there!
I'm in the middle of a move, but once I get settled, I'm hoping to be more scientific about my sourdough and grinder!