1. I had never heard that you shouldn't use metal lids because the alcohol would react to the metal; all of my tinctures are in 1/2 gallon jars with metal lids. I did however have a problem with a metal lid bubbling up where it came into contact with the tincture when I shook it but it took months to happen. It was the only tincture I made that called for apple cider vinegar along with the alcohol, it was the Lobelia tincture. I don't know if the ACV reacted like it did when it was combined with the alcohol or if it was just the ACV. Next time I tincture lobelia I think I'll try the Tattler lids and rings because they're BPA free but I haven't checked to see if the ACV would also react with plastic so I'll have to do more research before I buy them. www.amazon.com/gp/product/B0055PU5DC/ref=pd_lpo_k2_dp_sr_1
2. I purchased the tincture press that Uny and Rocky use: www.consiglioskitchenware.com/store/pc/LARGE-VEGETABLE-PRESS-8-20cm-STAINLESS-STEEL-IN-STOCK-527p2530.htm I ordered the medium because they didn't have the large in stock and they kept telling me that it was on the ship but since I couldn't wait I just bought the medium. All my tinctures are in 1/2 gallon jars and I have a lot of them so after using the medium a few times I went ahead and ordered the large when I saw it was once again in stock. The medium size is fine if you tincture quarts or pints, any larger than that and you'd have to fill the press more than once to get it all done. I don't see anything at all wrong with the press you linked if that's what you prefer.
4. Like I said, I use 1/2 gallon canning jars and from them I fill 4oz amber tincture bottles when needed for use. I leave the tincture in the 1/2 gallon jars until its gone.