Your plumbing supply house appears to be right on this one. Take a look at the Kohler spec. sheet for the K-7161. On the 2nd page Kohler has written in that the 17" - 24" tub height means an overflow height of 14 3/4" - 21 1/2". From your tub dimensions, your overflow height is 15 1/4", so the K-7161 should be fine. Good job, though, double-checking everything - that's how problems are caught :).

Hi, The gasket you describe is pretty standard it is placed between the tub and overflow pipe with the tappered side up. If the overflow doesn't leak when you run water into it then let sleeping dogs lay and rest easy if it leaks then change the gasket. Good Luck Woodbutcher

Basically there are two types of waste & overflow kits. If your finished tub will have a 12"x12" access hole,eihter through and adjacent wall or up through the floor from underneath you may use the common waste & overflow kit which has an overflow body with a long tube attached that makes the vertical riser from the overflow down to the Tee. The top of the Tee has a slip joint fitting so the tube from the overflow can be cut to length to fit tubs with different depths. The side opening of the Tee also has a slip joint fitting so the waste arm from the drain shoe can be adjusted for length. (Note: the drain shoe is the casting that fits directly under the tub drain hole) The Tee has an extended tailpiece which then drops down to the P-trap. The rough in fittings are universal however you will need to chose which type of drain stopper you want. They have the cable type, the wire rod type that connects to a lever on the overflow trim cap. a toe kick type which is opened or closed by tapping with your toe, or a lift & turn type that fits in the drain opening and requires lifting and turning it by hand. You will also need to chose which type of finish you want on the metal trim parts to match your tub spout and faucett handles. If your finished tub will be fully skirted and there is no access panel the code requires a "Glue In" type waste and overflow kit. The glue in type kits will have a cast overflow body, a tee, and a cast tub shoe. The installer then custom fits the connecting lines from standard schedule 40 DWV grade pipe and glues it in place. This type of waste & overflow also requires a glue-in type P-trap. These kits are also available with the different types of drain stoppers mentioned above as well as a broad choice of metal trim to match your faucett & spout. The advantage of the glue-in type is that all joints are glued permanent joints so there is little to no chance of a leak once it is installed. Although it is rare today, there still are some local codes that require all metal DWV piping. In those instances there is a tubular brass type waste & overflow kit available that is fitted the same way as the glue in type, but the brass joints are all soldered.

I just replaced mine. I was falling apart/crumbling. I didn't have the tool mentioned. I very carefully used a small dremel with a "grinding/cutting" wheel I found in my husbands hobby stuff to cut it in two and gently used a small chisel. The tool is probably best, but it turned out o.k. with me. FYI, the guys at Menards recommended using latex caulking material when replacing the new one. I didn't have much luck with that and used plumbers putty. I am a total novice though.