IMO there is not much difference between the Schmidt 888 rollerball refill and the Pentel Energel gel refill. In fact I changed the Lamy Rollerball refill to a Pentel Energel refill in this pen.

So here are a couple of suggestions: uni Alpha-Gel with the Pentel Energel needle-point 0.5mm refill - also available in 0.3mm and 0.4mm

You can also use the same refills in the Dr. Grip Limited Gel Pen.

The 0.3 and 0.4mm are available in red and blue ink, the 0.5mm refill is available in more colors.

If you are going to be writing on satin or glossy paper, the go with the 0.3mm Staedtler Triplus Fineliner which comes in many colors, including black.