For the most accurate information, we'd need to know part numbers of the alternators.
Generally speaking, no problem hooking the Bosch directly to the battery; that is essentially the way it is wired at the starter. Make sure the wire is sufficiently large to carry the current
, probably 8 or 10 gauge is good for relatively short distances. A ground wire of the same size directly attached to the ground point on the alternator
or the alternator frame is also necessary.
How the fields are excited will determine the characteristics of wiring
those circuits, if needed; a common method is to interrupt the circuit at either the on/off switch or 'I' terminal of the start switch.
If you have a tach and it operates off the alternator, again, the alternator design dictates the wiring
(and suitability), so a p/n is needed.