Dear McBenz
It is always better, if originality is not a priority for you, to have an alternator with internal regulation. That is more reliable since there are less interconnections Between components in your Charging system. Remember each component is a weak point, susceptible to have a loose connection, breaking the system.
An internal regulated alternator has only two prong connectors. One for terminal T30 (or also called Bat+) and another for the charge light.
If this later is your approach, then do not connect the external voltage regulator in the fender and open the connector that used to go to your previous alternator and use the cable which is red/blue as your lead for the charge light.
Installing a higher capacity alternator also means, that at least you have to upgrade the thicker cable going from alternator to starter terminal T30. Original pagoda cable for that purpose was only 4 mm2 in section capable of handling 28A. To eliminate that bottle neck you are creating With this change, improve that section of your harness to at least 10mm2, trough which A current of up to 53A can pass without major heat generation. 10mm2 equals to A cable size AWG 8. The conductor from your starter to battery is thick enough (As starters demand much energy during cracking from battery) so the excess energy generated by your system when car is running, will travel fast to battery and charge it effectively.
I am surprised that your car with such a small 35A alternator worked seamlessly with an Air conditioner unit. For sure your A/C system does not have a electric fan in front of the condenser (radiator) since that only accessory has a peak consumption of 15 to 20A. Leaving only (35-20) 15A for the rest of your car electricity users.
Any other question PM.
Best regards
L.Peterssen