The OpenBCI Ultracortex headset is a nice piece of hardware, but rather expensive (350-800 USD) and does not always provide a good fit with the subjects in terms of comfort and signal quality. Using loose wires with cup electrodes offers flexibility and attaching a few of them with Ten20 paste to the scalp is not such a big deal. The advantage of cup electrodes combined with Ten20 paste is that signal quality is usually better and that a single set of 8+2 electrodes can be used to cover all head sizes.
Robert recently got himself a 3D printer, and has been able to print us the OpenBCI casing used in the Ultracortex headset, in cool black. To facilitate the use of cup electrodes, we designed a head sweatband with the OpenBCI board attached to the back using Velcro. The electrode leads are then cut to length and wired to the EEG board using a 11×2 Dupont connector.
You can find all the info to make your own here.