RV Mobile Home Install- 1st attempt

First of all, many congratulations for the forum and to all the community that integrates this forum with valuable knowledge!
Have learnt a lot of stuff just in a couple of days.
However, with so many information in little time - and my poor english - I can say afterall that I feel brain foggy

So I would appreciate your help concerning my proper case and obviously I hope to learn more and more

I have an old Mercedes Bus which I made in RV Mobile Home... With lots of space in the roof I would like to be self-sustainable and as you usually say 'dry camping' (without conecting to grid)

Since my consumptions are not very critical was thinking about beginning with:

3x 255W 24V Panels
1x 30A E tracer MPPT charge controller
Lead Acid True DeepCycle Batteries?!

1 - First doubt: 12V or 24V Solar panels? 24V are cheaper. And will let me grow my system later till 1.5K for example. But for example my water pump and lights are 12V. Is there any problem? Can I 'take' 12V from a 24V battery bank? I mean, can I feed my 12v pump for example from a 24v system?

2 - Batteries: Depending on the 12V or 24V system, what do you advice? 2 x 12V? 4 x 6V? I was thinking of 4 x famous T105 Trojan ones...

3 - I have heard here about ''battery balancing''. Well, this is completely new to me How can I ensure that I dont make mistakes connecting my batteries? Even after checking the smartgauge schemes (method 4 seems more stable) I didnt get the idea of this method on how to achieve 24V with 6V models...

Thank you very much for the help and sorry for my poor knowledge Wake up for solar world just yesterday eheh

Thank you!