In my experience diving the long hose setup, both balanced and unbalanced second-stages work perfectly fine for necklaced backups. Unbalanced second-stages are just a recommendation that simplifies equipment configuration, in addition to reducing points to consider when preparing your equipment for diving. Balanced second-stages these days are adjustable, both venturi and air flow. By simply turning these down, it would perform similarly to a properly tuned unbalanced second-stage at depth. In my opinion, using a balanced second-stage for the backup gives you the comfort to increase the air flow should you need to do an air share for an extended period. For me, turning the backup with the mouthpiece facing down has done well enough to prevent free flows. Occasionally, it still does free flow when I jump/roll off the boat, but its a simple quick action to turn the regulator facing down again.
Now, with regards to having a necklaced backup with an inappropriately long hose length - it's not ideal, but it's fine to work with. You will have to remember that the hoses bow out more, sometimes way past the size of your body frame and IS a hazard. As such, it's better to use a removable bungee/surgical tube loop (such as those sold by Dive Gear Express or Diving Solutions), rather than attaching it permanently to the second-stage with cable ties. In the scenario if something gets caught in the hose, at least there's a breakaway connection.
Your desire to better yourself in diving is admirable! Here's my humble suggestion - dive the necklaced backup with the equipment you have, until you feel ready to switch out the hoses. Using both hose lengths allow you to experience the differences, and why the Hogarthian system is designed the way it is. Also, while doing so, it trains your muscle memory to use your necklaced backup, rather than reaching back for the octopus in an emergency, like what seaturtle and darrenlowjq have mentioned.
Using a long hose/necklaced backup and a backplate/wing does not make it a DIR setup. It's just a Hogarthian setup. DIR is a holistic system whereby your fellow divers (team) dives a similar setup, and everyone comes together in a single frame of mind to accomplish a goal diving. To find out more about DIR diving in depth, you can check out courses by both GUE and UTD, as they operate on the same principles. GUE courses are conducted by Living Oceans and Living Seas in Singapore, while UTD courses are run by Rainbow Reef. They run fantastic courses in preparing you for team-based DIR diving and is essential in your next step towards DIR, should you choose to follow that school of thought.