Hey, I have a bambino which uses the same portafilter. 17g is a nicer dose to work with. Also really you shouldn't use the razor as you are essentially changing the does you just grinded and wasting coffee.
I bought a tamp and distributer which helps me wedge all the coffee into the basket and keep the shots nice and even. You'll probably be told to use a WDT which is a definite luxury.
https://www.amazon.co.uk/gp/product/B0896Q41R9/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
Link above for tamp and distribute.
Also, this all applies to the double unpressurised basket
I wouldn't waste your money honestly, while its grinding shake the handle of the portafilter a few times. It will also help with the distribution instead of having a heap of coffee grounds in the middle of the basket the shaking will help level it out evenly in the basket.
If you really want one just search amazon for breville dosing funnel 54mm. This is the style of one that works with the Touch https://www.amazon.ca/SCORATE-Espresso-Breville-Portafilters-Hands-Free/dp/B09PZ7TF7M/ref=sr\_1\_8?crid=MKL3KXLZJV87&keywords=breville+dosing+funnel&qid=1658382009&sprefix=%2Caps%2C107&sr=8-8
I have a $60 cuisinart burr grinder that does a fine job of grinding coffee for drip.
Just for convenience alone, I'd rather use a second grinder for drip coffee so I'm not changing the grind setting on the Breville all the time.