Hello all! used a factory 30 deg kick attached a factory 90, and measured. Stub height measured 14 1/2 inch. I needed a 28-1/2 inch kick, so I cut a 14 inch nipple and then measured, (14-1/2+ 14= 28-1/2) my kick ended up at 24 inches to bottom. I,m not sure if I,m doing something wrong here, Can anyone advise me of the math formula I should use when using factory 15,30, deg kicks and factory 90,s sent out to job. I,m just not sure if I am using wrong formula here. Thanks much!