Very smart you people, yes, that was the issue, it has the space and i figured out just when i left there, sure next time when i will shoot i will put it the first one closest to the lens.
But, if i will use another filter with it such as .6ND or .9GND, which one should be first closest to the lens? Sorry, i mean only ND and CPL, i always put my GND last further away from the lens if used with other filters, if only 1 filter i use then i should be smart to put any single filter on the closest slot of the holder to lens.
Big stopper always closest to the lens then it doesnt matter for the CPL or GND etc.
With regards to timings I find that by big stopper is 11 stops (yours may differ).
Procedure I use - I usually set up everything without the big stopper but with any CPL and GND and take a test shot. I then click the dial 33 times (3rd stop increments for 11 stops). I then put the big stopper back on and take the shot. If the 33 clicks of the exposure dial takes me past the 30 second maximum I switch to bulb mode. If for example I get to 30 seconds on the 27th cllick I know that I still need to go another 6 clicks (2 stops). I would then go to bulb mode and take an exposure of 2 minutes. Obviously this will vary depending on the shot but its just an explanation on how I do it. Others may have better methods.