As far as I noticed, fishing is just a requirement to craft gold pans but it doesn't affect success chance or exceptional chance. Same thing with begging.
With 100 tinkering you still cannot make gold pans, with ~110-120 tinkering you got a small chance but with ~150 tinkering you get 100% success rate. I recommend to buy "Gloves of Hard Worker" which will give you +10 tinkering and tinerking power scroll. To go further, you will need to get magical cloth items with +tinkering skill from Random Magical Cloth deeds or by buying them from other players. Also talisman with extra success/exceptional chance for tinkering can be very useful. You can get talisman like that from tinkering quests in Heartwood or hard monsters like peerless bosses.
Feel free to PM me (Ciparnieks) in game if you need any help with Gold pans - i can answer questions or craft some for you.