Hmm well, I renamed all the sprites properly (i.e. ammo.png, brok.png, sbox.png, shel.png, bon2a0_h.png, bon2b0_h.png, bon2c0_h.png, bon2d0_h.png, medi.png, stim.png, bstr.png), put them into "hires" dir, zipped it and loaded it with GZDoom (latest build, r918) by adding it to autoload section in my zdoom.ini file. This works just fine for the DHTP and other custom files. However, these sprites do not want to show up ingame... weird.
Anyway, I think this project should be continued and finished, especially since the models which you can download in different flavors are mostly poor attempts to imitate the originals. Also, if I am trying to use the (monster) models with GZDoom, terrible lags would occur. GZDoom is the port of my choice, and I do not want to use others like Doomsday. What we have seen in this thread until now looks really promising, and I am sure that once this is done, many will prefer using this over any model pack.

However, I guess especially the monster sprites will take considerable time and efforts to recreate faithfully.