I'm with ya on using spears for bales and forks for pallets.

...But, I've broken 2 single deere spikes on heavy silage bales... so I've converted the only boughten spear frame we have to doubles near the bottom.  And have built several others for our other loaders and for neighbors, all having doubles on the bottom of the frame.

My reason for putting the double spears in the bottom of the frame are two fold.  First:  you can lower the spikes to just a few inches above the ground and use the full lift height of your loader (if the extra height is ever needed, like on the skidsteer stacking hay 3 high in the shed--2 on end and another on top of that). Second:  when stabbed above the center (most of the time) stability it unmatched.