I agree that it should not be necesary to do so ahead of time, but I would ensure that you do so immediatley on signing the lease and make sure you have more than the minimum requirements and offer to allow them to meet the dog, etc.
I am currently looking for another place, and while I am in another country, as Brooke is a service dog legally I cannot be discriminated against on the basis of her, but the simple reality is that they could refuse to rent to me on the basis of anything at all. I have references from each of my immediate neighbours, vet and trainers, all testifying to Brooke's wonderful behaviour, health, etc, etc. One of my neighbours is muslim and she has written that also. Brooke has never ever barked, and I will always have her with me when looking for places. To me I do not want to take the risk that they have problems and so I have a whole resume for Brooke, along with plenty of references, all with phone numbers and other contact details. I also have letters form all my doctors and therapists testifying to my need for her, and how much she supports me. I do have a copy of the relevant legislation if needed, but I have no intention of forcing the law, I just want to reinforce that the legislation does support these dogs. Research certainly shows that the more evidence you have of the dogs behaviour, training, health care, etc the more chance you will have of finding rental accommodation. Make sure you offer to pay pet deposits, etc if relevant and offer to sign extra clauses on a lease if need be to say that you will always look after the dog. I also ensure that they are fully aware of the emergency procedures that I have in place for the dog, should I become ill or injured, as the last thing an landlord wants is to be stuck with a dog, and having to decide what to do with it, etc.
I agree with the starting with pet friendly properties and even those that only allow small pets are going to be more acceptablde to those that want none at all. Be as prepared as you can be, and have all the possible available evidence to support your well behaved, healty and temperamentally sound dog. Make sure you mention how you ensure the dog has plenty of exercise and mental stimulation and is not simply left to bark all day.