I don't recall if there is a chart from RM2 that shows a dosage amount to be applied, but I know there is a chart that lists how many PP's of magic an item can hold. You could use this as a guide for "How many doses are needed for a weapon." That just popped in my head as I was getting ready to write my response and I wanted to get it out before I forgot.
We handled poisoned weapons thusly:
- One dose per weapon. The poison only needs to cover the part of the weapon that will actually be penetrating into the opponent. You wouldn't put poison on the flights of your arrow or the shaft, only the arrowhead. A 2H axe only needs the cutting edge to be coated, not the entire surface of the axe-head (both sides), or the haft.
- A crit other than Krush needed to be attained in order to "show" that the weapon bypassed armour and pierced the body to allow the poison to be introduced into the organism.
- The poison stayed on the blade only for 5 rounds of fighting (not attacking in a round didn't count) before it needed to be reapplied to the weapon.
- If the attack was high enough to appear on the attack table but yielded 0 points damage, it didn't count towards the five rounds. It was considered a blocked weapon or ineffectual attack with the "wrong" part of the weapon.
- If it yielded concussion damage, but no crit, it counted towards the five rounds. The attack had the intent of delivering the poisoned bit into the organism but hit armour and wasn't enough to penetrate the skin, therefore some poison was wiped off on armour or clothing.
- Once the poison was successfully delivered into the organism, the poison needed to be reapplied to the weapon, whether it was the 1st round or the 4th round. The attacker couldn't successfully poison five targets with a single dose on a weapon. After entering the organism, the entire poison dose was effectively used.
It seems restrictive in that the attacker needs a critical and a non-Krush crit at that, but the attacker is given five chances to introduce the poison into the body. Upon success, the organism needed to make the Poison RR or start to suffer the effects of the poison.