A question to Ahmadis

I was not talking about contemporary issues, but very basic issues of fiqh. For example, should we fold our arms when praying or keep them straight.

Out of four fiqh's of ahle sunnat, which fiqh did Mirza follow?

There are four masalik instead of one due to disagreement on rulings. But only one of them can be right at one time. Now since Mirza said he was a prophet hence he should have combined the teachings of four imams. He should have said that Imam Abu Hanifa was right on this issue and Imam Malik was right on that one.
I am looking for such a book.