RA4 is colour, yes? If so, I agree. I remember in my study years ago, my main tutor was telling us we could develop colour prints in exposed trays etc. I didn't get a chance to try, for I didn't have access to a colour enabled darkroom. However I crossed paths with another tutor at that photography college who warned me NOT to try and just use the closed machines they have available. He proceeded to tell me that one of the other students went and did it and consequently burned out her sinuses and that my tutor shouldn't be suggesting it. Putting two and two together I'd suggest its doable but go and buy the best gas mask you can get and make damn well sure the place has state of the art ventilation!
On the subject of huge prints, I still aim to try that one day when I find something which is applicable to do that big. Cut my own rolls and somehow find trays big enough (for B&W). So Im quite intrigued about this type of topic.