Link in / out – questions – General

Hi,
in my project I have 10 flow and 5 dashboard for as many tablet.
In every dashboard I have text, button, switch, gauge, ecc. ecc. and I like change, label, color text, background color, ecc. ecc. based on temperature, alarm, sensor motion, door sensor, ecc. ecc ……

To send value between flow I often use the node link in / link out, but I use these node also inside the single flow to have a better view of the same flow but at the end these node are a lot, about 12/14 for flow …..

There is a limit to the number of node link in / link out?
Into a flow, is better use these node or “pull” a line? (link)
Well, is this the better solution for my function?