I believe using Math SE as an assistance for self-teaching is a great idea, for the following reasons:
First, I believe it fits the scope of the site very well: This site focusses on math, that is sub-research level (as opposed to MO). Thus problems appearing while self-teaching should fit in very well.
Secondly, the SE concept is about questions being answered in a way that the generated content will be valuable to future readers and not only the OP. While having your proofs verified may appear very specific to your own situation at first, I believe that in fact by asking such questions you are providing excercise material for other learners that are on the same level as you are. A good answer to one of your questions would in general point out problems with applying proving techniques you may have and also suggest improvements in notation.
To elaborate on this consider the following situation: You encounter a problem that can be proven by a standard trick that you however are not yet aware of, so you attempt a different way to prove it. This sort of question directly motivates two sorts of answers: A description of the standard-proof as well as answers relating to your alternative proof, that may in fact be viable, possibly after some corrections.
Having multiple answers and pointing out different approaches to a problem is at the core of the SE concept and thus again, what you are doing fits in very well and generates value for future readers.
Whenever you post an attempted proof this is valuable even if the question remains unanswered, because if anybody with the same problem ever encounters your question, they have a starting point in your proof and may be inspired to retrace your attempt and thus learn from your work. With an unanswered question a good description of your attempt will even additionally motivate people to work through your proof, as they could be the first to answer!
Third and finally by having your own attempts verified you are acting as a positive example: Too often we have questions asking for quick solutions without providing own work. By showing your own work and asking for feedback, you are doing the opposite and you are showing, that learning requires own thought and effort.
In conclusion you are certainly not violating any "unwritten rules". Also you should not worry that you are asking too many questions: This site does not work like a store in the sense that you would have to pay for every answer you are getting with an answer of your own. To stay in that picture, rather think of it as an account with a very wide credit-margin: Once you have gained the expertise you strive for, you may be better able to provide answers on your own and pay back for what you once received.
Also the very sort of question you are asking already constitues valuable content in itself, even if lacking an answer, and you should not be concerned that you are taking more than you are giving.
If you are not receiving any answers it ist most certainly because your questions are hard to answer:
On the one hand, your subject, algebraic geometry, is very specialised and requires a lot of dedication: Unlike basic calculus, linear algebra, functional analyis or stochastics, many students graduate without having acquired a basic knowledge in algebraic geometry. Thus it is probably harder to find somebody who can answer even a basic question about algebraic geometry than to find somebody to answer a basic functional analysis question.
On the other hand, your type of question (verifying proofs) is typically more work to answer than a question that could be completely answered by providing a well-known standard technique. Somebody to answer your question will be required to work through every aspect of your very personal proof and even might attempt to work around and correct some minor errings in order to make your general approach work. If you are self-teaching you may not yet be familiar with the usual ways of presenting the argument in your field of study and your proof may thus be hard to read for an expert. This very nature of your question might thus reduce the amount of persons able to answer even further, as not every expert may have the time that would be required to provide a quality answer.
So please do not be discouraged by a lack of answers and keep it on. I personally am very happy to see self-learners questions and the type of question you are asking provides a strong motivation to me to invest some time in an answer.
PS.: I am sort of sad now that I have quit algebraic geometry after giving it an honest attempt... I have by now forgotten everything I might have ever known about it, otherwise I would attempt an answer to one of your questions now. ;)