I've used this on goretex motorcycle clothing and I'm impressed with its performance. I treated my jacket and trousers 2 months ago and have been through a lot of serious rain while wearing my biker gear since. There was only 1 day it let in a little rain on 1 arm, which was a particularly bad, flooded day where I was riding for a good hour and a half. The rain was battering down. I've since been on other very heavy rain days for maybe 40 minutes each time, where road spray is absolutely drenching me, but once I get home and pull my gear off, I'm dry underneath. Genuinely impressed, as I would normally have multiple wet areas with the same clothing untreated. Being on a bike in the rain with a cars road spray covering me is a serious test for this product.
What worked for me: I did a quick rinse and spin to clean the washing machine. I put 1 item of clothing in with the quoted 100ml of Tech Wash. I put it on a 30 minute wash with a slow 600 speed spin at 30c. Afterwards, while that item is still damp, I added 100ml of TX Direct. I put it on the same 30 minute wash with a slow 600 speed spin at 30c. I let it dry naturally.
This worked for me and I'll be buying it & when it finally needs reproofing.