I came across this on the Historical Diving Society Australia-Pacific facebook page, a guy was talking about building his own shallow water helmet and posted some pictures of it. He then went on to talk about his other project which was to convert a Scubapro R190 into a twin hose. I have no idea if these links would work to show you all, but I thought that the forum members here would find this interesting.
https://www.facebook.com/groups/1209509 ... ment_reply
https://www.facebook.com/photo.php?fbid ... =1&theater