I am still a little lost as to wire gauges and what my alternator is to see if suitable for a specific dc-dc charger.
I have this one in mind for good price to feature ratio as the bigger ones are double or more and don't think I need that much as this is just to supplement solar in these shorter days or if they would even be compatible with the alternator:
https://www.12voltplanet.co.uk/sterling-power-bb1225-battery-to-battery-charger-12v12v-25a.htmlI am not sure what power my alternator is so will have to wait to find out. I looked in the manual today and could not see mention of an alternator in terms of specifications and forgot to look under the hood when I went outside and am now inside for the evening.

Also what wire gauge should I use? A support rep on 12 volt planet wrote me that 50a cable with 30a fuse will suffice. I am confused by this since I read an article on split chargers today that stated you should choose wire that is the amperage of the charging unit (which would be the alternator right?) but also that the battery can also be a charging unit so you should add both together. I know the battery is 60 or 80, can't recall exactly and then also add the amps of the alternator, currently unknown but probably up to 100 or more so why did they tell me only 50a wire? Does the above advice on split charging not apply in this case of dc-dc charging?
Any other considerations for setup? I thought initially I would have to drill another hole to get to the engine from the cab however I remembered I have a whacking great 100mm hole in the floor for an intake fan so I could run it through there couldn't I? I believe there is space to fit the wire without interfering with the fan. That would make life somewhat easier.