LSD possession is generally dealt with under state drug law and each state has somewhat different limits. [although the criminal code act also has provisions under federal law]
As Marklar already stated, in NSW the limit is 15 DDU [discrete dosage units] or 0.003g. The average blotter is under 60mics, so the 3mg would equate to about 50 non-divided doses.
In the case of blotters you will be charged with the number of DDUs, so as long as you stay under 14 units and don't have any other obvious dealer paraphernalia you would be charged with personal amounts.
If you however have 50 doses in liquid form you will be charged for the total weight of the liquid, ie if liquid runs at 1ml per dose then 50 doses would be 50ml and hence the charge would read 50g of LSD. In most cases this will be amended JUST before you go to court to whatever the actual LSD content was, however this is not guaranteed. It appears that prosecutors no longer like convictions under the 'full weight' legislation as it leaves the judgement open to challenges. But again, there are no guarantees. And in any case, you will be treated as a 50g LSD criminal right up to that point. And 50g of LSD is 25 times the large commercial quantity, which carries a potential life sentence. So you see how different your treatment might be [eg bail amounts] for having 50 liquid trips instead of 14 paper trips.
Also note that DDUs are limited to 200mics. If you go over this then you will be prosecuted by weight. ie you can get away with putting 199mics on a super large blotter and then cutting it up into 4 at point of sale/consumption, meaning you can carry 4 times as many super blotters than standard commercial blotters. This appears to have been one reason for composite blotters released in the 90's where the perforation was around a large pattern which had faint lines printed onto it dividing it by 4.
