Finally I decided to make some order into my two networks and to see what can I do to make better single network out of current two.
Currently I have mixture of Mikrotik and consumer-grade equipment spread on two networks (one private and one public) but I would like to migrate fully to Mikrotik and make one single network.
Below is roughly diagram of what I want my network to be:

What I want:
1. Single network
2. Load balancing two internet connections
2. My private computers, smartphones, devices, etc (whatever I decide what's private) to have full access (unlimited bandwidth, traffic, access to NAS, etc.), no matter where I connect (different APs, LAN, etc)
3. Guests devices to have access to internet only (limited bandwidth, daily traffic limit based on MAC address, etc)
4. Use CAPsMAN to manage all access points, to use single SSID on all APs and to successfully roam clients across APs
I know it's a lot but I'm not sure how to start.
I have lot of questions and I would really like if you guys can help me.
Some of the questions are:
- What would be the best way to make private and public parts of network ? Do I want to use multiple SSIDs (one public, one hidden) on APs or some other way ?
- How to limit bandwidth and daily traffic ? Can I make limits based on MAC address ? Example: every MAC address (except MAC addresses from my devices which are excluded) get 2Mbit bandwidth and 1GB traffic in 24 hours. After 24 hours that MAC address get new 1GB limit.
- Is CAPsMAN and same SSID on all APs best solution for my property coverage and client roaming ?
- Since in my are 2.4GHz spectrum is low density, should I stick with it or do I fire up 5GHz radios on APs too ?
- If I use both 2.4 and 5GHz radios, how do I manage it SSID-wise and CAPsMAN-wise ?
- Would RB3011 be best buy solution to carry my network ? I expect no more than 50 guest clients connected on all APs during peak hours. Usually it's around 10-20.
Thanks in advance for any help I get. Also, if you need more details I'll be happy to provide.