So, I went and fished up the specs page, and it looks like it will run in quad channel. So, 4 or 8 matching sticks won’t matter there.
If you’re worried about CAS latency, well, that depends on the RAM and not the board. 32 GB sticks will probably not be as quick there, or it’ll just cost extra.
Opinion: If it were me I’d just go for the 32 GB sticks. Leave room for expandability with a matching kit if needed, and not sweat winding up with a sliver more CAS latency.
this is something to be said about rank interleaving and having more ranks, but having more ranks also tends to be rough on the memory controller so it limits the speeds you can run them at