Awesome man! The back lever is definitely a skill to be proud of. I’d say generally keep doing what you’ve been doing, but I’d suggest utilizing straddle back levers for your workouts. If you can hold a full back lever for 3 seconds then you can probably hold a straddle for a few seconds longer, which is substantial. It will allow you more time in the position so you can become more comfortable and efficient with it. Once you can do a straddle back lever for like 15 seconds then try going back to the full back lever more regularly. I don’t know your amenities but I recommend getting a video of yourself or check a mirror because you want to make sure that you are indeed level and that your back isn’t arched.