I realize the train has left the station, but two other comments for the record.
1) Will a 3296W trimpot physically fit in the space allotted for the 3362P - without bumping into the cap or bridge? It's a little longer/wider and it would require a new pad to be dropped on the board since the terminals are in-line albeit on a 2.54mm grid. The idea is to allow either style of trimpot to be inserted. The 3296W is multi-turn as used in the ubiquitous LM2596 stepdown regulator modules that we have come to know and love. Same cost on eBay when I just looked. This might be a nice project for someone getting started with DipTrace and could take Rod's existing design and make a minor modification with a high likelihood of success while contributing to the cause (in my opinion of course).
2) For some applications with low-current, it might make sense to install the TO-92 version of the LM317. Might be even cheaper depending on where you buy. The idea here is very few designs come anywhere near requiring the >1 Amp capability of the LM317T. In fact I seem to recall real-user data where the current required in a passenger car LED application was 5 mA (or less)! In such a case there's no need for the TO-220 version which of course is a rather large package. Commensurately, you would not need a 1000uF capacitor to achieve a suitable flicker reduction...and could use, say, 220uF or less which would allow even a smaller overall space requirement. Again, the idea here is to create what amounts to an Application Note for Rod's board design. I suppose if someone learning DipTrace wanted a simple modification project to get one's feet wet, they could add 3 pads on a closer grid to install either the TO-92 package or the TO-220 package (same PCB board)...and contribute to the cause (in my opinion of course).