I converted and played "Rough Busines" from Pavis GTA to MRQ2 and I also started to convert "The Celestial Engine". Of course there are no stat blocks in HQ2, so, I simply decided how the opponents and NPCs should look like compared to the HQ difficulty of the contests and the strength of my players. However, at the end I always handwave difficulties if they get out of hand. I also finished converting "Kakstan's Art Museum" from Ian Thomson. I think it was in HQ1, but not 100% sure. I did more or less the same, sadly we never played it (until now). "Converting" from HQ to RQ works fine, as in fact it is no converting, but simply an own creation of the opponent values/stats. As long as they are properly decribed in the book it is quite easy to create them from scratch.