It depends - I draft them for clients in NYC (we've been doing a ton of disclaimers lately) and it takes me about 1-2 hours to draft the document and then draft all the required notice documents. It depends how involved everything is and how accessible the information is (I had one where I had to go back and forth for accurate land surveys, it had to be filed in multiple states to ensure proper chain of title, we didn't have everyone's contact info, we went to client's home to personally oversee her signing, multiple parties were disclaiming, etc).
For a very simple disclaimer, it would probably take me 2 hours to review the statute and draft 1) the disclaimer 2) the notice docs and 3) assemble all the related exhibits, including the will, description of property, etc. and send everything out for signature. When we receive the signed document back, then we have a secretary or paralegal file them (at a much lower rate) and send out documents to everyone who will have their interest 'accelerated' because of your disclaimer.
So..I'd say 2 hours of work at the hourly rate plus if they have a paralegal who bills out file it, then maybe a half hr or so of their time.