BBQ: Add Propane Connection with Y Connector

Question

I live in Western Europe, where there are two common types of gas cylinders for BBQs: butane and propane. I have a BBQ (second hand) that came with a butane bottle and regulator of 28 mbar. The BBQ is clearly marked on the front that it's compatible with propane at 37 mbar.

I'm interested in switching to propane, as I've heard it's better at lower temperatures, and I use the BBQ regularly even during the winter months. I understand I will need a new regulator as the pressure and interfaces aren't compatible. I was in the store looking for one when I saw a Y connector, like this:

This got me thinking, would it be possible to use some extra hose and a Y connection to have both these regulators attached at the same time? Would I need to add shut off valves between the Y and the regulators to prevent the higher pressure propane from reaching the butane regulator?

Answer 1

Propane and Butane bottles at least here (Italy) have the exact same bolt-type connector or the vendor-specific 'fast' connector. I suggest you to buy an adjustable regulator : so you can increase or decrease gas pressure upon your needs.
To see if pressure is correct just look at the flame, it has to be blue without orange tips, if you see most flames turning orange you have to decrease the pressure if flames are 'sad' you can pump it little up.