+1 on the tripod.
Big Stopper for the Lee holder - I have screw-in 10-stop NDs (B+W/Schneider), they're good but you can sometimes alter zoom on an extending lens as you screw it on. The Lee makes it easy to compose, meter and focus, then change exposure and slide the filter into place.
I sometimes use both the 10-stop and a CPL.
Do you face problems with vignetting using both the 10 stop and the CPL at wide apertures? I tried doing this with the Hoya screw-in filters (NDX8 and a CPL) on the 24-105 @ 24mm and the vignetting was terrible.
The only issue with using both LEE Big Stopper and LEE CPL is that you need two foundation kits ... Right now I'm waiting for the Big Stopper as well as the second foundation kit having been on the notify list of B&H for over 2 months
5D3, 6D, 600D, RX100
16-35L, 24-70L II, 70-200L II, 100-400L, 50L, 85L II, 135L, 24TSE, 40, 100 macro, 18-55 II, 55-250 II, 600RT x 4
I come here to learn something new, not to learn how bad my gear is - I know that already ;-)!