Yes, you can use it as a bench PSU. Of course you'll need a case, and some binding posts (4pcs) for the output voltages.
(Actually, my first project back when I was 17 yr old teenager is a regulated Bench PSU... 1.25V to 20V using... guess what... an LM317 chip.)
If I were you, I would not solder the PCB trimmers.... instead, get some pots of the same values as the trimmers (5K) and just wire it to the PCB from the front panel.
Now, since this is a bench PSU, and the amount of load this will be connected to will vary, I'll probably use a bigger heatsink. And since I designed all the regulators to be on the side of the PCB, it will be easy to install a big heatsink with fins... (and from there, you can even get fancy and also install a fan to blow on the heatsink, you can buy 110V fans... but I think it will be overkill.)
WARNING: If you'll be using a SINGLE heatsink to connect all 3 regulators to it, you MUST USE TO-220 insulators for both the regulator and the mounting screws. You can buy this at digikey and other electronic hobby shops. The insulator will prevent the back of the vreg from touching the aluminum heatsink and isolate the mounting screw also. Then, mount the aluminum heatsink to the case for further heat dissipation.
NOTE: Since the kit for use with the SC-1 does not require a big heatsink, and we're using separate heatsinks for each Vreg, and the heatsinks are not touching any part of the case, we're able to get away from not using any TO-220 insulators.
As I said, Using the above mods, with a 22-0-22 transformer, you'll get adjustable output from 1.24volts to 28+ volts.
Using a 20-0-20 trafo, you'd get 1.24 to about 24Volts.
So I don't think you need a separate PSU for +/-14V. Since the 24V outputs can be adjusted down to 14V (and lower) if needed. The minimum voltage is 1.25V. i.e. you can't reduce the psu to below 1.25Volts without any major changes in the design.
One mod you can do to your PSU is get one of those digital meters that you can hookup across your outputs. Then you'll have a digital readout of the output voltage. You can buy them at eBay.