Tap revivers

hebron

My kitchen tap is one spout with a hot and cold seperate handle either side of the spout.
I bought tap revivers kit mainly to change the cold tap as this messes about but I will do the pair.
I stripped the tap down and took the cartridge out, but the new one although is the right size for the tap the length is a little shorter. You do get extra washers to fit on but the instructions are not very clear. It tells you to measure the seating depth to work out the extra washes need but I don't know this. Do I just judge it but what happens if when you fit it and put the water back on if it's not fitted correctly.
I was a bit unsure so I reassembled the old tap to find out some more.
Any advice would be great

Thanks

keystone

Why on earth not just buy the correct cartridges for the tap?

Cheers

hebron

Because I went to the plumbers merchants with the cartridge and they said identifying it was impossible so this was the only option. If I could has bought the correct cartridge don't you think I would have done so. I'm not an expert I only take advice from others.