Thanks again to everyone for the feedback. No, George, my FEL can't lift anywhere close to 2200#, so the weight rating of the forks themselves is not a factor that would eliminate the lighter-duty 42" forks. And Pappy, I will check out my ability to see the tips of both 42" and 48" forks from the seat of the tractor.
Everyone's responses drove me to check my memory about the weight of other attachments I have. The grapple weighs about 400# and the 4-N-1 bucket weighs 456#. I have been used to a larger tractor than our current
L3800, but I have been pleasantly surprised at what I can lift even with this heavy bucket on the
L3800. Our FEL is the Kubota LA524. If I am reading the FEL manual correctly, the rated lifting capacity of the FEL is a max of 1182# about 5' off the ground about 20" in front of the pins of the FEL, and a load of 855# to the max height of the FEL. (I don't much care about what the max-height capacity is, since I won't be lifting any load anywhere close to the max height.) So, if this is accurate, if I subtract the 238# weight of the lighter 42" forks, I would be able to lift over 900# 5' off the ground, and if subtract the 340# weight of the heavier 48" forks I would be able to lift over 800# 5' off the ground. I very much doubt that I will be lifting this much weight. And I think I would have a ballast problem if I did try to lift as much as the 1182# (I do have loaded rear tires but my box scrape, which I use for ballast, is not very heavy).