British rules differ from American rules.

I'll do American rules first, as they're easier...

"If you would" is perfectly okay. The difference between "If you would" and "If you were to" is that "If you would" is a polite request, whereas "If you were to" describes a situation which is either impossible, or expected not to happen. For example, compare "If you would make tea..." with "If you were to complete that Rubik's cube..." Also note that there is a difference between "If you make tea..." and "If you would make tea..." The former is a simple if/then statement about the consequences of tea-making; the latter is a polite request.

"If you could..." means "If you are capable of...", and so is not a request. If you said to me "I would be thankful if you could answer my questions", I could answer "Then be thankful, because I can". It's grammatically correct, but it doesn't mean what you want to say.

"If you should..." means nothing at all. It is nonsense. As a statement, "You should..." means "You really OUGHT to...", or "You have an obligation to...". As a question, "If you should" should really really mean "If you really ought to...", but that doesn't really make much sense.

And now for the British rules....

The British rules are the same as the American rules except in the first person. In the first person (I/me/we/us), the meanings of "would" and "should" are interchanged. Use "would" wherever Americans would use "should", and vice versa - but only in the first person.

In practice, British rules are not used very much these days, even in Britain. When occasionally you encounter them in use, it often serves to confuse rather than clarify.

Rommie

Anonymous

“there isn't really any noticable difference. You wouldn't use should in that statement. ”

You do realize, don't you, that you are answering a question that was asked almost six years ago, and that the person who asked the question is not likely to still be waiting for the answer?  That's enough time to finish a university degree! 

CJ