Down to personal choice but i prefere the externaly regulated alternators,,,,easier to repair,,,,also,,the regulators job is to regulate the voltage going to the battery by altering the amount of "FIELD" voltage to the alternator,,,,,more field voltage= more out put from alternator.
Externaly mounted regulators can be full fielded if necessary, making the alternator give it's maximum out put,,,,caution is necessary though when doing this because now you have unregulated voltage from the alternator.
As to your question of should you go for a higher amp alternator:
Absolutely,,,,,,stock alternators are usually woefully inadaquate to the tasks we give them,,,,,and dont worry,,,when you dont need the power,,,the alternator will not give you any more than you need.