It really depends upon the type of diving you are planning to do.
Let us review for a moment the function of the BC. The BC does 2 things:
First: The Buoyancy Compensator (BC) is necessary because you have to be slightly negative (hopefully about -1 lb only) to sink. Wetsuits are very positive (they float) especially 7 mm ones. To get negative you put on lead weights. Once past a certain depth, the neoprene (if diving a wet suit) compresses and losses its buoyancy and you really no longer need the lead so no you are more than slightly negative. So you put a little air into a BC to offset the weight of the lead. In my case with my 7 millimeter wetsuit, 7/5 millimeter hooded vest, gloves and boots and AL 80 tank, that is 20 lbs of lead for salt water diving. How much lead (include any metal back plate if you dive on) do you wear? If you are diving a drysuit, you will wear more lead because of the buoyancy of the air in the drysuit.
Second, the BC helps you float on the surface. You need this because you are slightly negative by a pound or two because of all the lead. So here you need a couple of pounds of buoyancy with you and a wet suit in the BC. With you out of the BC and just to float your rig on the surface while you get in or out of a small boat or inflatable you will need more lift, equal to the weight of all that lead (you do not have the lift of the wetsuit) and other equipment. So you are back to the amount of lift required at the bottom.
So now to your question is 60 pounds of lift overkill. I dont know. Depends upon you and your diving. But for me 44 pounds is over kill. Heck a BC that has 30 pounds of lift for me and my diving with a wetsuit and 20 pounds of lead is plenty. If I had a dry suit, then I would mostly need 40 pounds or so, but since that is way outside my pocket book, I really do not know how much lead I would need then.
Bottom line, it is your diving and your equipment, buy what you are comfortable with. Ask the salesman for an explanation of why you need 44 or 60 pounds of lift. That should be interesting. The BC is NOT a lifting bag or elevator. The only thing it is doing is Buoyancy Compensating (hence the name BC) for the loss of lift due to compression of the wetsuit. How much lift does the BC you use now, or in training have? Did that work. Remember more lift equals more size, which full or empty equals more drag in the water.
Now I must leave to compress my wetsuit again with a couple of dives.
