Look it’s you’re dive setup and especially when you come to sidemount you find that people begin to setup their gear differently. I think going pass 6” hose is way to long but it’s your choice. I personally wouldn’t have it but that’s up to you. I would say across the board with wetsuit, drysuit, even in a birthday suit the norm is 6”. I wouldn’t go out and start buying every single little thing though. I think you getting a new system and another sidemount class will help out beneficially. The main reason why I say taking the class again is because most sidemount instructors teach on one platform and know how to properly fit you.
Before I switched to transmitters only, I used 6” miflex hoses diving dry. Worked fine. I liked how they were more flexible. Also agree with taking the class again.