I am right now an archer with 5 PD and 155 wpf and this is the bare minimum wpf i would suggest for 5 PD. (right now i am 15/21)
For 6 PD, I think the recommended (for good accuracy) was no less than 160 wpf.
This is of course in very light armor, due to the wpf penalty: 14 wpf per PD (i think, but something along those lines), and the armor weight afterwards.
If you have experience as an archer and have a pretty good aim, then I would suggest you to test it, something like this build (at most)
Level 30 (4 420 577 xp)
Strength: 24
Agility: 15
Hit points: 59
Unused skill points: 5
Skills to attributes: 8
Ironflesh: 0
Power Strike: 0
Shield: 0
Athletics: 5
Riding: 0
Horse Archery: 0
Power Draw: 8
Power Throw: 0
Weapon Master: 5
One Handed: 1
Two Handed: 1
Polearm: 1
Archery: 146
Crossbow: 1
Throwing: 1
It will be pretty unaccurate, but if it hits (especially with bodkin arrows) it will give a neat punch. You wont be able to run (ah, going in EU 1 and in my first round causing a draw, the pleasure
).
And yes, bodkins give pierce to every bow, I have more than once when leveling up shot someone with a low tier bow and still hurt due to bodkins.
About accuracy, it will be bad, as your effective wpf will be 35 (so good luck). The longbow will suck, your reticule will get huge before you can actually release the arrow.
For something more realistic, I would go 21/18, my build below:
(this is coming from someone who has been a pure longbowman for 2 gens with 21/18)
This one isnt pinpoint accuracy either, but it is doable, at least i could do it:
Level 30 (4 420 577 xp)
Strength: 21
Agility: 18
Skills to attributes: 8
Power Strike: 4
Athletics: 6
Power Draw: 7
Weapon Master: 6
One Handed: 10
Archery: 154