IMO you only need your bow to be strong enough to 1-shot bandits for now. If you can' t 1-shot yet and don't want to risk upgrading just get more str+int eq. Of course you can also just upgrade it to +5 if you intend to use it pass the lvl 24 bow. I'm lvl 28 and I'm still using my SOM+6 lvl 16 bow since it equals a lvl 24 sos+3. I also got 20%(100%) AR increase and max block ratio on it. Play around with alchemy with your bow. It's worth it when you see the final product. =)
As for farming, when you get to the 1-shot stage, you should be able to get 1150 sp per hour with gold ticket. Just control+click everything in sight and if a bandit giant spawns (not bandit archer giant), hit that with zerk too.
Then again the sp you manage to farm and hour depends on how crowded the place is. In my case, most people didn't stay around my area long after getting fed up of my 1-shot killing all the mobs around.
