Is it necessarily to practise tubes of light meditation to be successful diamond dowser? Is it enough to practise SFQ?
One of the important aspects to take care of when dowsing is to be a clear channel when you do it. Sometimes my morning meditation feels as if it has already done that for me. At other times, I will do the Tubes of Light, because I feel as if I have some energy to clear before I can tune in and really feel, hear or see what is coming through.
I've used the Violet Flame for many years, because it has such an immediate impact on any stagnant or foreign (absorbed from others) energy in my field. If there's any doubt that you are clear, I would definitely do that and/or the Tubes of Light before dowsing.
It's highly likely that your Spring Forest Qigong practice has a similar impact, so tune in to what it feels like to you. I think we're all far wiser than we give ourselves credit for!
All the best!