Clearly Gas's power was insignificant before he became the most powerful in the Universe.
From the way the brief fight between Bardock vs Gas Transform is shown and the way Monite talked about Gas, it makes me think that Gas Transform was more powerful than Bardock, but the latter defeated him in some way, it will be maybe with a special attack or Transformed Gas had some weak point due to his inability to control the form.
I think Morph Gas's boost over his normal state should be something similar to Zarbon's boost.
I think I have something like:
Gas = 4,000
(Transformed) = 5,600
Bardock = 5,000