Tikz inline plots

I’m using the Tikz package to create a series of plots directly in my main .tex file. I opted for this method because the labels match perfectly the font and size of my main file even if I scale or not the plot.
Now I encountered a common problem that is the one related to the TeX capacity exceeded. The suggestion to overcome this problem seems to be to externalize the plots. About that I have two problems

1. If I create the plot outside my main .tex file, will the font and size of the labels be math with the main .tex file even if I scale the figure?
2. If yes, can someone describe the procedure to follow? I searched on other threads but I didn’t fully understand the procedure. To write my .tex files I use TexMaker.