I have a chart with:

Quesitor Merc. Rx. in the 11th House - at 11 Taurus 43' 53"r
Sun in the 11th House - at 2 Taurus 18' 38" (The Sun represents the subject I'm asking about - if an email will be accepted well -"Communications" 3rd House is in Leo.) Sun is representing another important part of the question - the friendship - it's a question about friendship being accepted in an email.

My question is - how do you find out what is degree, what is minutes, what is seconds? Is it Cazimi or Combust and if the Sun is the signifier - does it still act as the "Combuster?" Or do we take it the Subject Signifier only?

Any help is much appreciated.

it's not combust because the Sun is a signifcator in the question.

Maxz, I'm not sure what you mean. What you described would be Mercury under the beams of the Sun. Combustion is based on a certain conjunction orb of all planets, whether they are significators or not. Most give it about 8.5 degree orb, under the beams around 17. Cazimi is within 17 arc mins, meaning a conjunction that is partile (same degree) and also within a certain arc min degree. Cazimi is rare, and Mercury is not cazimi Sun yet.

If you are combusting someone else, you may be overwhelming to that person or cause fear in them. If someone combusts you, there would be a flip side. I have asked about a falling out with a friend before and she was combusting me and would not respond to a friend request I sent her online (for a networking site). Sort of like a rejection, I guess. In another horary (which is on here somewhere) I asked about a long-term friend who stopped speaking to me last year, and he was combust by someone else (a third party) and did not respond to me either. Combustion is considered a form of prohibition, so it's not so nice to see in a horary when it represents important significators. It's common in love horaries though because people tend to lose logic and have a lot of passionate feelings/fears, etc.

Sun in the 11th House - at 2 Taurus 18' 38" (The Sun represents the subject I'm asking about

If the Sun represents the subject you're asking about, than the damage caused by its influence also has its meaning.
Mercury is burnt by the the sunbeams rather than Combust as Tanit has already pointed out but. though, on a brigther note, this influence is weaker that combustion, the sunbeams are still descriptive of some sort damage and the fact that it is one of the significators that is exposed their heat does not mean that this type of influence does not count but quite the contrary - it means that we have a relevant planet exposed to the sun beams; one of the relevant planets is actually damaged. How it should be read will depend upon the rest of the chart and of the situation in general but in this particular case, if Mercury is actually the ruler of the Quesited, then we have more than one strong alarm sign because, currently, this Mercury is not only exposed to the heat of the Sun (and receiving its application) but also retrograde and, thus suffering from (at least) two accidental debilities.

If you are combusting someone else, you may be overwhelming to that person or cause fear in them.

I agree that the situations where the ruler of the Quesited is represented by the Sun (the combustor) are very interesting.
I may want to add that,when L1 is combust by the ruler of the 7th in romance charts- the promise is generally anything but good; the Querent is blinded and weakened by the presence of this planet and this placement usually provides an almost literal description of the realistic circumstances and relationship. The Quesited's ruler being the representative of the negative influence is usually clearly suggesting that the problems actually come from that very direction- from another person (the querent is overwhelmed, madly in love, not seeing things clearly, weak...a potential victim).