There isn’t really a way to call in requests around the time they are doing room assignments.
I have my TA add room requests to our reservation when we book it. I also usually have a Touring Plans subscription when we have a trip planned and have used their fax request service, but personally we didn’t have better results with that. Others seem to get good results though.
I have had zero luck with the online request form. Which isn't working for me at this point anyway.
I've had best success with the touringplans fax request (which requires a subscription).
Otherwise I would call and make my request by phone at the regular booking line (or if using a TA they will make the request). There is no way to call the hotel directly. The direct phone numbers listed online get you an operator at a central location and not the people doing the room assignments. The room assignments are made about 5 days in advance so I'd be sure to call before 5 days in advance.
I call Member Services and have them note it in the reservation. We're about 50/50. And with the 50% unsuccessful, they seem to do their best to fulfill one of the two requests we make, e.g. BWV standard view, "across from the bus stop/high floor" is our usual request; we've had both and we've also had one or the other.