We certainly didn’t get through the whole tube in the month we used it, I found it in the bathroom cabinet a couple of months back and there must have been half a tube left in there (chucked it, now I’m pregnant there’s enough dampness down there day and night!) I think they sent about 6 applicators but I never used a full one, it would have been an interesting level of mess 
I only used half of one each time, tops. We did a loose version of SMEP that month and from looking at my chart I used it when we DTD from getting a flashy smiley on the Clearblue. So that’d be 5 times - 3 flashy days (2 x DTD) 48 hours of solid (2 x DTD) and then the ‘one for luck’ the day after.
It’s difficult to know what role it played, I’m definitely not holding it out as ‘this was the thing that did it for us’ but I’d been using the Clearblue digital for 5 cycles at that stage and we’d been pretty diligent for DTD on the static smileys, so who knows. I figured I was spending enough on the ovulation tests so the cost of the lube wasn’t much in comparison!
That said we’ve agreed that we’ll use condoms and cycle tracking after DC1 is born rather than go back to the pill. When we’re ready for DC2 I hope I’ll then be in a good routine with my knowing my cycles, but I’d probably also use preseed from the start, just in case it was a factor this time around.