I never try to fill the hollow plates, it's not necessary, when the plates are full is when the pumping gets much harder or impossible and you need to open the press and clean it to start fresh. Unnless I have a lot of syrup to filter, like maybe 2 barrels worth (My barrels are 26.5 gal SS) I rarely ever end up with full hollow plates when I break down the press to clean it. Some of that depends on the season, no two years are the same, most years the amounts I gave work well, some years I need more. That is determined as I run the mixture of DE and hot syrup, if the filtered syrup takes too long to Sparkle as I run it back into my mixing pot, I add more DE, but that is rarely needed. From there, I close the filtered valve after opening the recirculation valve and I move the filtered discharge hose to either a barrel being filled or to my bottler. Then I open the filtered hose valve and close the recircultion hose valve. From there, I keep an eye on the pressure, when the filtering gets harder I slowly open the recirculation valve sending some of the flow back into the mixing tank. If while filtering I need to open that recirculation valve over 1/2 open it tells me, I need to change the papers and stat fresh after cleaning the press. On my press (A Lapierre from about 2007) the pressure should stay below 40psi or I risk bursting a paper catching the DE. That's what I watch. As I understand it, the Smoky Lake press or maybe it was the clear Leader press or others can run at higher pressures, for that consult your press manufacturer's directions. My only experience is with my Lapierre Press, initially with 3 sets of plates, then with 5 sets as it has now. You need to realize the DE amounts I gave are for my press a 7" Lapierre, other sizes will use different amounts of DE. The larger the press the more DE you need, and vise versa. It all depends on how much surface area your press has, both on each plate and times the number of plates. I'd think it would be simple math. If your press has 100 Sq inches per plate, that 2x whay my press has (49 sq "), I have 5 hollow plates, if you have more or fewer just do the math.