I would advise going towards a board:
- wide enough for your weigth (mine is 30" 1/4 for my 100kg), to have power in mellow waves
- extremely thin in the rails, especially in the tail and the nose.
- a flat rocker
- a wide tail will provide power for gutless waves
This way, the thiness with give you insane, fluid manoeuvrability, the thin rails and flat rocker in the nose wont brake when you go to the nose.
You can see my 2 "longboard" shapes in the photos: left one is a performance shape for hollow waves (narrow), the right one is a dream for old school riding in mellow waves (140 litres, 9'6"). These are Gong boards, but are difficult to get (you have to preorder them, and preorders are full in the 2 hours following the announcement...)
I think the Laird Pearson are good boards (avoid the non-Pearson Lairds)