Add tranny drain line?

Hi, I wonder is this is feasible:

I have a 1996 Acura Integra with rather dirty automatic transmission
fluid.

Changing it a time or two or three seems a bit messy...

What do you folks think of addling a little drain valve on the
transmission cooler line? It looks like a not too rugged 3/8" hose.
Could I put a 3/8" tee and valve on the line so I can decant a few
quarts with just a flick of the valve?

The local car parts store guy said it's a really high-pressure line
and recommended against it, but it looks like a not too sturdy hose
with two flimsy steel hose clamps.

Any ideas appreciated.

 

Additional parts that can fail.

 

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What's 'messy' ? You run it until it's hot, unscrew the plug, drain 3.5
litres out. Wipe shavings off plug, reinstall plug, top up with 3.5
litres of Honda Z1. One week / 100 miles later you do it again. What's
so messy? I use a painter's tray to catch it, and save it in a 4 litre
jug for recycling. YYopu don't even need a special wrench, just a 3/8"
socket handle.

You didn't mention your mileage

'Curly'