If you read bhai nand lal jis rehatnama, Bhai mani singh's book" sikhan di bhagat mala", Bhai prahlad singhs rehatnama and sarabloh granth,its clearly written and asked to guru sahib regarding guru roop. In bhai Nand lal jis rehatnama, it is written that Guru sahib has 3 roops, Sargun, nirgun and shabd roop.
1. Sargun - panch bhootak roop- It was panch bhootak roop of guru sahib whe he was present before joti jot and then that has been given to- khalsa panj payare/sangat ( aapan roop khalse deena, dutia roop satgur grantha - Sri sarab loh granth) ,( Guru Khalsa manyo pargat gura ki deh- Bhai prehlad singhs rehatnama- early 1700, which was changed to guru granth ji manyo pargat guran ki deh by giani gian singh in 1930),
2. Nirgun sareer- Which is jot and is present everywhere as it is submerged in waheguru and waheguru is everywhere, so guru sahibs nirgun sareer is everywhere, inside us, out side us where ever you see and where ever you cant see
3. Shabad guru- Dhan sri guru granth sahib ji maharaj,Shabad guru surat dhun chela- satguru nu sab koi dekhda jetha jagat sansaar, dithyaan mukat naa hovayi jichar shabad na kare veechar- as shabd is gian guru, so thats why even when guru arjun dev ji was present in harimandir sahib, still the chor and hukamnama was done on guru granth sahib maharaj. Our gian guru says that guru is everywhere, so it is not the deh of satguru .
Regarding parkarma, now guru sahib is present every where, in sangat, in guru granth sahib and inside you. So you tell me which side would you face. It is similar to guru nanak sahib in makka. So i think it really doesnt matter from gian point of view to do parkarma from any side. I know nihang singhs do it in opposite direction and i think it is just a tridition, people may think that it may be more respectfull to guru sahib but guru sahib who is present in side you all the time in both nirgun and shabad guru roop knows what you do 24/7 and it is more important to stay in bhe and bhavni of guru sahib all the time doesn't matter, we are doing parkarma from left side or right side., i would love to hear veechars from bhai kulbir singh ji as well. And one more thing, singhs can wear shastars on bot sides of body and they can carry it in their hands, dulammla, so in other words, sings are loaded with shastars in all directions of their Body, so it really doesnt matterin which direction you do parkarma as long as you do with nimarta and bhe bhavni of guru sahib, waheguru and sangat.