I'm new to music theory. I need to know more about the maths behind it.

I have two questions.

Before I ask - the temperament I am using is the most common; 12 TET with A tuned at 440HZ.
With that in mind I am willing to accept answers that use true tuning or others if it answers my question.

So I began by listing the most consonant sounds in relation to C starting with the most consonant to the least.

I found they were in this order (Again, in relation to C). G,F,A,E,D#,F#,G#,D,B,A# and then C#

So I understand that this is supposed to be due to wavelength and the frequency in which the waves of each note (roughly) match up, with every 3rd wave of G matching up with every 2nd wave of C (Making it the most consonant) and every sixteenth wave of C# matching up with every 15th wave of C (Making it the most dissonant).

Question 1:

I have a problem with the naming of these notes - I absolutely know that this is because I don't have enough information. I think if I tell you what my problem if you might be able to tell me what I'm doing wrong.

So from C to G is a "perfect fifth". I know this is because G is the fifth step of C Major.

G to C is a "perfect fourth". I know this is because C is the forth step of G Major.

I see that, according to the information I have and what I can hear, that G and C are the most consonant notes that aren't the same note.

If I understand the naming correctly (Which I know I don't) why is the most consonant note in G major a perfect fourth and not like C major, a perfect fifth?

Question 2:

My main question. Is there a way I can get a visual representation of 12 TET?

I would like to see for myself how close each note is to each other in the hope of getting a better understanding of the sound behind them.

Ideally I hope somebody can point me to a program I can use that shows the waves of a note and I can play more that one at once.

Thank you in advance.