May have been a little too enthusiastic to offer help.
By connecting the wires as I described you will be able to get full AC output from the alternator and therefore full DC output from the rectifier. This will need to be regulated in some way. If you are changing to 12 volt then a Lucas Zener diode would be the cheapest solution.
If you are retaining the 6 volt system simply connect the same coloured alternator wires to the new rectifier as are currently connected to the old one.
However, if you are fitting one of the many aftermarket rectifier regulator units, then I would expect full installation/wiring instructions to be delivered with the product.
I have a Boyer rectifier regulator unit on one of my BSA’s and it works brilliantly. Supplied with comprehensive wiring instructions .
Can’t help with the carb, my 29 flyer has brass Amal.