My IR at Stapleford took around six weeks from start to test pass. This was with me training around six days a week.
This allowed for one session in the aircraft/Sim a day with the rest of the time spent backseating, revising or planning for a subsequent flight.
The IR course on the DA42 says 15hrs DA42 time and 2 hours for test and 35Hrs SIM time...
Most IR courses give around 25hrs flying time....is 15hrs not a bit on the short side?
I found 15 hours to be plenty of time.
The Sim used for the course is a really outstanding representation of the aircraft. All the students I spoke to found the conversion to the real aircraft to be a non event. Remember, you have the exact same G1000 panel in front of you in both the aircraft and the Sim and the handling and performance difference between the two is negligible.
Feel free to PM me or reply to this post if you have any questions.