If this is an add on, you wont need to take the written because you already have it. ARCH 89U is right, just check the regs. Regarding slicing the minimums in half, part 97 states that only the visibility may be cut in half but no less then 1200 RVR, you may NOT cut the MDA or DH in half. Flying an instrument approach in a helicopter is done at 80 knots and once the FAF is crossed it is increased to 90 kts, which equals about 480 feet per minute on the VSI. As for the actual practical in a chopper, at least 3 approaches (one precision and 2 non-precision), tracking and holding, steep turns, and unusual attitudes. Plus the oral going over regs, procedures, well you know! Most DE's dont have you file an IFR plan because of time but they usually ask you to fill out the written flight plan with an appropriate route on airways and such from one airport to another. Any other questions, just post.