sog question

i was reading al b's sog and was wondering when you are doing a sog and you ave plants in a bunch of different stages how do you flush the plants for the last couple weeks would you need a spereate resevoir and tubes pump ect for the last table to flush with water with no nutes? im trying to figure out how to set up a sog with this 60 site table im looking at but im not sure how it would work i think it only has one res and i dont know how to add on

I am also planing to do the same as AL so i have been reading his pos alot aswell, the way Al has it setup is he has 4 tables, 4 res ect the table you are looking at is one big table with the res to match so your not going to be able to change the nutes to match the stage of the plants as the res will be flooding that one table it means that the if the plants are at diff stages they are going to loose out you are better to try and get 4 dif tables with a res for each or try to work it out with that one table for week 1 -4 and then another table for the final 4 weeks