I edit the 2da file so you can have up to 24(25 with 0?) parts with 9(10 with 0?) colors each. To do that, I alter the minRange and maxRange values in the 2da so that it reads 10 to 250. Technically, the unaltered file gives you a range of 10 to 100, which grants you 9 parts per section with 9 colors each. I personally like to max out my weapon variety, and randomize treasure output, so I ramp those ranges to 0/255 most times.
The toolset can open items which already have their part indices set to numbers out of bounds, but you cannot just drop and use parts above those set in your 2da files. I tested to make sure, by removing the modified baseitems.2da. Doing that removed any entries from the dropdown which were over part 9, but the item still shows as I had constructed it earlier with part 24.
If you know what range is still available in your PW, I can modify the file names so they fit your needs. Or you can view my 24-part module and alter them yourself when ready. The way I have it right now, in the toolset, you just change your top/bottom/middle all to 24/1. I made you a blank mid/bottom at #24 so you don't have to pick those parts, but still have a proper item icon.
I don't understand the want to make hak-free PW? I think people are misinterpreting the ability and benefit of hak files. Not to mention the ease of modifying single 2da files. I guess that discussion has been going on in other threads for years, no reason to split and take it on here again.
Not sure how it looks in whirlwind. I personally hate vanilla whirlwind. It looks really stupid for weapon weilding PC's, IMO. I use a custom 4E system (with encounter/daily special attacks), where all the units get a set of 4 custom special attack animations. This overwrites whirlwind and a number of emotes, depending on the creature. But that is a story for another time.