The spacing won't be exact, especially since the advance in a Holga is manually according to the numbers on the paper. But, there is probably more room at the tail (untaped) end. I find it easier to load the taped end into a reel anyway.
So, if you adopt that method, spool it onto the reel then cut a bit off the end.
You can also check your fix time by just watching the progress of your film. If you check it at say, 1 1/2 minutes and it's clear, you know you need at least 3 minutes total.