I am sure the guys at B3 will be able to advise you. If your previous bat worked well (with regards to weight, how about middle position and pick up?), then I would use that as a starting point. Have you tried other bats that you like?
You mention a bouncy home pitch - How are the away pitches (do you need an away bay and a home bat, perhaps?!).
I would suggest the most important bits are shape/ weight and pick up (I'll take good ping as read). Then see how much you wish to spend, which will determine the grade.
Good luck and enjoy the trip to the in-laws...
David