there are differences even between sunni muslim prayers and this has been the case since early on. the differenes of hand positions aren't contradictions but rather they result from how ppl saw the prophet (saaws) perform salaat. all of the ways are acceptable and having right aqeeda is all that matters. the madhabs are not sects or denominations nor do ppl follow the scholars whom the madhabs are named after. we all follow prophet Muhammad (saaws) and the scholars or imams were aware of their differences in certain rulings. may Allah guide us to the straight path and unite this ummah between both sunni and shias, ameen.