It sounds like you have already given this a lot more consideration than the segment of the jump industry with whic I was associated. I do recall the intial discussions [training] I had as the jump pilot, during which I asked about jumpers contacting the aircraft (Cessna 185 in that case). I was told that it was considered a goal to attempt to touch the horizontal stabilizer on the way past, and it was very rare to be able to. I asked that no such attempts be made on my flights. One thing I came to understand is that some freefallers like to "fly" upon exit. If the aircraft had a lot of speed on jump run, this was easier for them. I used to slow right down on jump run, usually to 50kts. This probably had the affect of making touching the tail even more difficult, should they attempt it.
There was never a concern about the parachute canopy contacting the airframe. Jumps either involved a freefall, or for student jumpers had the jump master deploying the pilot 'chute by hand as the student exited. The only caution I was given was that if a student decided to not jump, and chose to risk landing back with me, I had to disarm the barometric release system, or I would have a cabin full of parachute, which if it worked its way out the door in flight, would be a serious problem. I suppose word got out about what it was like to land, as everyone always decided the 'chute was the better way down!
I'm sure that there are different level of "professionalism" among jump organizations (I suspect mine was in the "less" category, which was why I stopped flying for them). I certainly saw a cowboy attitude at times, and would worry that if something could be imagined, it would be attempted. That increases the risk of injurious events.
I suspect that the infomation you seek may not so much exit formally, but rather as "tribal knowledge" among jumpers and pilots. You may have to state the aircraft type, and ask if anyone has flown them in jump operations, and has experience, but as it's a twin, it won't be me!