I have added both a Hauptwerk virtual organ system and a pipe organ to my Johannus console via midi. All three can be played from the console independently or in any desired combination. Playing all three together can be quite impressive!
I too have built a hybrid begun in 1975 as pipes alone until Ahlborn Archive modules came along. In 96 I moved into a house which I had remodeled with the organ in mind. I added Hauptwerk and was off to the races. I can attest that the sum is better than the parts. I've since removed upper work ranks which are common to HW and replaced them with 8' stops which add the most to the whole. I couldn't be more satisfied with the results. If I can help, don't hesitate to ask. Doug
I added a fairly complex Hauptwerk addition to the pipe organ at my church. This may be more involved than you expect, but details are at: https://almorse.net/content_OrganUpgrade.html
AL, Thanks for your CODMs, encouragement and assistance over the last few years which has allowed my project to realize excellence I could've only dreamed of. Doug
I've recently added a Teensy based capture system to a 4-rank Moller that had lacked any pistons and real SAMs. It would be great to take the next obvious step and pick up the key contacts for Hauptwerk. I'm happy to share any info on the project. I hadn't posted previously as it is not a HW project at this point though the organist and myself would like to see the church move in that direction.