used to make a lot of these for the timber frame outfits I did a lot of work for ..... 150 x 90 PFC ... didn't put a full length under plate on them though ... just three tags for the forks to fit into ... thick ones ... kept the weight of 'em down ... and as said, couple of ears for retainer pins behind the fork heels
they must've had 10 sets of 'em littered about the factory .... saved hunting for a set when they wanted 'em ... 2 acre site full of timber frame panels and stock .... extensions were on/off like a whore's draws