This just replaces the default tail of the Spit Mk IXc, so just drop the file into the mods folder and check it out under the Spitfire Mk IXc. personally I recommend doing a bit of playing around, for instance i added the folders "SpitfireMkIXcCLP(GB) and "SpitfireMkIXcCLP(Multi1)" into the 3do folder of the mod (eg. "Modname"\3do\) to give the tail to the LF.Mk IXc for all countries as well (easy step to this is find SpitfireMkIXc(GB) and SpitfireMkIXc(Multi1) in the 3do folder, copy them to another location, rename them to the CLP ones i've listed above, and paste them back into the 3do folder). Another recommendation on my part is to delete any file that doesn't say Keel or Rudder in it from this mod. Because while the mod as is adds a historically correct rounded-top tail to replace a historically correct but less common later pointed-top tail, and adds a historically correct small air intake under the nose instead of the also historically correct but later large air intake, the addition of the air intake replaces the historically accurate later Spitfire windscreen from the Mk Vc onward with the completely historically inaccurate early windscreen found on the Mk Is through Vbs. Deleting everything but Keel and Rudder files will give you the rounded tail, but leave the larger air intake, and the correct Mk IX canopy. This way i figure it's better with three completely historically accurate parts than two completely historically accurate parts and one completely historically inaccurate part. Just my suggestion though mate. Hope this was helpful, probably WAY more than you were looking for but hey, you said "any advice" hah!