You could try Dr Thomastik mandolin strings which give a considerably softer sound. I believe Gore Elixir do mandolin strings now but I haven't tried them yet. If you prefer phosphor bronze, Newtone strings, a small handmade strings business in England, will make up sets to any gauges you like and do a postal service. If you're interested let me know and I will post up the details (I haven't got them with me at the moment).Best regards,
mcmoo