The bracket looks aluminum, and I was worried I might crack it if I overtightened it. I wonder if that might be what happened to the old one. I measured from the top of the rubber to the cross-member and it is about 30mm, so it seems a fair guess the PO replaced them.
As luck would have it, a thunderstorm knocked out power here for about an hour last night and I pulled out the lantern and started reading the Haynes manual which arrived last week.
Listed right after the crankshaft oil seal is:
Engine mounting to engine mounting bracket bolts.....41 ft/lb
Engine mounting to crossmember bolts.....30 ft/lb
Engine mounting bracket bolts.....18 ft/lb