Digital BW, The Print

I liked the way a couple of my black and white on-screen images looked with a light sepia tone. 

For prints, I am using an Epson 1400 with the UT-14 inkset and Red River Fine Art White paper. Using the printer-controls settings, this achieves good neutral results. Replacing the UT-14 Ebony ink with the black ink from the color ink set is a little warmer and the blacks are a bit deeper. 

I've worked a little with the QTR software and tried a few ICC settings to see if I can nurse some warmer tones out of the UT-14 ink set. This has not worked well. 

With on-screen images I can acheive a nice sepia tone with the following method. Save the B&W image as a JPG. Open the JPG in Lightroom as a color image. Adjust the color temperatuer +12 (adds yellow) and adjust the tone +5 (adds red). This simple adjustment has me thinking. Can I achieve similar results by adding a bit of yellow and light magenta to my black ink and get a sepia print?

I have ink in bottles and a few spare cartridges that I could experiment with, but before I start, it seems pudent to ask if others have tried this. If so, what works?

My questions would be:

- What ratios of black to yellow and or light magenta to use (or other colors, if recommended)

- What cartridges in the UT-14 set should have the additional toning? Do they all need it or just black?

I'm inclined to try adding about 5% yellow to the color set black along with 2% light magenta and mix that with the other 5/6 of the UT-14 and see what happens. 

Comments would be appreciated.