i am a bit late to this party, but have a couple of thoughts
as for the listeroid, yes do tear in all down and clean it thoroughly before you start it. be especially mindful of the underside of the piston, right above the wrist pin (grudgeon pin in england) as there is often sand stuck up under in this area and it will fall down and enter the big end brg oil feed holes.
there was a time when plain upper shells were available for use with a hollow dipper, this modification was a big help in longevity of the big end brg on the con rod and the crank pin.
as for charging, you have the two options, AC generator and the charger vs the 24 volt alternator
the AC generator typically will be about 80% efficient then factor in perhaps 80% for the chargers efficiency will net you approx 64% overall efficiency,,, maybe a bit better but likely not over 70% on a good day
now the leece neville "if" it is a 24volt oem unit, will likely be no more than 60% and maybe less at high output levels...
having said that "if" you can get your hands on a 12 volt unit it can be made to generate at 24volts for battery charging with an efficiency that will be very close to 80%
it will reliably deliver about 3-3.5kwatts and be thermally stable, to do so it will have to turn at about 4500rpm, however this should not be a problem with a serp belt over the flywheel driving a suitable sized pulley on the alternator... most of the 10/1's turn 1000rpm and have something just under 24inch diameter flywheels iirc, so it should not be hard to accomplish.
i don't like the use of a 24volt alternator for 24volt charging, the reason being they are almost always wye/star connected and the stator resistance is the predominate factor in efficiency loss in these alternators.
i keep beating the drum for the 110-555jho because it is a delta wound machine, using a short stator stack 16 poles instead of the more typical 12poles and uses less wire in the stator,,, which means less resistance and less heating losses. the 555 alternator has proven to be 80% efficient at producing 28.8vdc @ 100amps continuous at 4600rpm, and do so thermally stable while using only about 35watts excitation.
remember also any other AC alternator or generator will also have to account for the rectifier losses that are already factored in with the 555's 80% efficiency.
fwiw,
bob g