They have at least two variations in slip ring diameter for their regulators. You fellows are aware slip ring replacement is possible as well? Not for size but to deal with excess wear. They are cheap as well. Basically I ignore the individual given specs and just put what new one I have on hand in. As long as the diameter requirement is met.
Have not had any trouble with this approach over the years on bosh volkswagon alternators. Mercedes are very simular.
One problem is the cost. There is a tremendous spread on pricing for regulators. I think the bosh unit is the best but some of my aftermarket ones cost about three dollars and have stood up well.
I see no way you are going to damage your battery. Basically they all function about the same. Call an alternator repair shop and price a regulator there. You can also address your general questions to them.