I have not made it yet but this may be the year to do so, I am interested to hear other specifics as well, like lbs per gal or even variants blended with other fruits.
I started a small batch last spring which is still bulk aging, but first did a test. I weighed an amount of petals, put them in a cup and poured over a specific volume of hot water. I did the same thing with another cup, but used cold water. I let both cups sit in the fridge for about four days and did regular tastings. The hot water test had a flavor that I estimated to be 3-4 times stronger than the cold water test. However, the cold water test preserved floral tastes and aromas very well, unlike the hot water test, which had a more "earthy" taste, in lack of a better word. The hot water test was also more bitter (although, still a usable flavor).
I decided to go for quality over quantity, cold soaked, and used 200 g of petals (yes, only yellow petals) per liter. I made about 7.5 liters, which amounts to a lot of picking and even more work with separating petals from flowers.
If you haven't made dandelion wine before, I suggest doing the same test before starting the batch. In order to create the best chances for success, the must should taste great IMO.