I´ve been wondering about the difference between MT90-16 and 130/90-16. From some manufacturer´s chart these two seem to have almost identical dimensions, so I was thinking MT90 was something special, probably for Harleys and such.
I have an almost spanking new Metzeler ME 77 130/90 on a spare rim, already, but may very well try a MT90, if necessary.
The front tire (3.25 - 19) has load rating 54 (212 kg) and the 130/90 rear has 67 (307 kg). Together they will be good for 519 kg, if ideally distributed.
The bike weighs in @ 220 kg, naked but filled. Me, m´lady, luggage and all will be at least 260 kg. Totally, with some margin, just under 500 kg. But - most of it will no doubt be carried by the rear wheel. Worth thinking about!