PBS is awesome if you know how to use it well. But yes, it's not the most user friendly up front. There is a learning curve to it for sure but it is incredibly powerful and flexible.
At 50% (assuming 50% of G-Line), you should be able to limit your flight hours using a SET command no problem. That said, the LCFs were high across the board for March so you're not going to get a line below that regardless.
The stuff I've seen from BidNav and ProBid or whatever is kind of a joke.