Any fining agent will speed up the process. If you want to try sur lie / battonage, it makes sense to not use a fining agent up front, so fine lees drop.
If you're using it late in the process, don't rack first. You'll need to remove enough wine from the carboy so you can stir the wine. Add the kieselsol and stir for 1 minute. Wait 5 minutes (or whatever time you want), add the chitosan and stir for 1 minute. Then restore the reserved wine. The sediment you stirred up with drop, and there is evidence that more sediment means it drops faster, as it provides more nucleation points for clumps to form and drop.
If you have ANY dissolved CO2, stir gently. If not, make sure you capture the volcano on video for the edification of your friends on WMT!
I barrel aged 2021 FWK without fining agents. When I drained the barrels in November, I treated 23 liter of each wine (Forte Super Tuscan; Forte Merlot/Petite Sirah/Syrah) with K&C and bottled the remainder. Two weeks later I bottled the two reserved carboys. In a few weeks my son and I will blind taste the 4 wines (fined and unfined versions of both wines) to see if adding K&C made a difference, and if so, what difference.