GRX crank with Ultegra groupset I currently ride a full Ultegra di2 setup with 50/34 chainrings and 11/32 11sp rear cassette.  I would like to run the GRX 46/30 chainrings because 50/11 gearing is a waste for me.  I could either stay with the 11/32 and get a lower gear or move to 11/28 and get tighter spacing.  Both my crank and the GRX are Hollowtech II, but I note the chainline on GRX is 46.9 mm while the chainline on my FC-R8000 is 43.5.  Is the chainline set by the crank or the bottom bracket?  If it is set by the crank, it this enough to matter?  Will a GRX crank work on the bottom bracket I have?
It's set by the crank, and is like this because GRX is targeted at 135mm/142mm rear ends. GRX takes the same BB as any HT2 road crank.

It's enough to matter, but chainstay length is the other piece of how much it matters. Doing this kind of thing on super short chainstay bikes can yield pretty compromised results in terms of number of rough combinations, and at the other extreme may not be such a big deal.