Cool jig 52...
I'm sure most of us Philistines, have ventured down the path of making our own, however, when I consider the adjustability of yours and the hardware supplied, I often wonder whether it's worth it... I don't necessarily think that the search for a gap fill project is that legitimate excuse... maybe "I must have one immediately" might pass the pub test.
The one thing I don't like about it is the IKEA nightmares I'm going to face for the next few months.
If your first cut is too short... Take the second cut from the longer end... LBD