Then since stone is too light you can use iron for the weights, or lead if you don't care about lead poisoning. they're both way heavier than stone at about 7.8 and 11.3 as opposed to 2.3, they would both fit one block. Or just use directly an anvil as the weight and have an iron plate unter it.
However you can also make that 3 blocks high stone pillar into one block high with the same science behind the magical 1mq crates made of common and regular wood that are able to store 1280 mq of dirt, if made of special wood they can go as far as to store 1600mq of stuff.
And lastly, about your practical note, the answer is :
Right now i have a barrel full of brandy for each berry plus 2 more barrels full of aqua vitae.