Question for Monz on Marchetto

In http://www.ixpres.com/interval/monzo/marchet/marchet.htm Monz writes,

>Since the 7-limit ratios would have the same letter-names as the 1:1, with
no >accidental, and since the 3-limit system would have to be an enormous
46-tone >linear system, which doesn't seem very likely for Marchetto's time
and place, my >suggestion is that his monochord division here was an attempt
to accomodate the >5-limit intervals given above.

Hi Monz,

Can you explain why the 3-limit system would have to be a 46-tone linear
system?