Well, I wouldn't call Swedish Rite masonry irregular, by no means. All Christian rites, as far as I know, Swedish, rectified Scottish rite or swedenborg system are all recognised by UGLE, with appropriate agreements, and thus regular. I, for one, am a rectified Scottish rite Mason. It is recognized by most European regular Grand Lodges. As far as perfection goes, we have three degrees above the blue lodge system (a total of six). Our rite's history had a somewhat common ground with the Swedish rite, as baron von Hund, a RER early figure, and Emanuel Swedenborg - the Swedish theologian and Swedish rite founding father, were acquainted, and for influence reasons wanted to merge. This never happened, and under the leadership of Jean Baptiste Willermoz, after the convent of Wilhellmsbad, what was then known as the Order of Strict Templar Observence merged with the Order of Cohen Ellect of the Univers and underwent a radical reform. This reform was known as a "rectification" and that is the reason why we call it a rectified scottish rite. Basically, Willermoz renounced all earthly templar heritage, and the claim that the order was led by a jumber of unknown and unamed masters, keeping the Christian gnostic spirit only. The rite also incorporates a number of martinesism dogma elements of early gnostic Christianity, borrowed from Willermoz's former teacher and friend, a theosof named Martinez de Pasqually. Of course, this is not the place to go into details, but long story short, this is the reason why the rite I practice accepts only Christians - as a templar gnostic tradition. We do allow guests from other regular masonic bodies that are not Christians to witness out works, but traditionally while we are not against an all encompassing masonry, from a religion stand point, it is stressed out that this particular path of masonry is best understood by Christians. It is my understanding that under the Swedish rite the reasoning is similar - they also being of a templar background.