[Marco]

My question: Is there the proper way to cut a T-track channel in a table saw/ miter gauge sacrificial fence board ? How should I setup my router table for proper dust collection for this? The dust and debris was flowing/flying out to the left, channeled out by the very slot I was cutting.

The proper way is to have the channel cut safely and completed as intended. I have cut them with a plunge base and on the table. Both have pro's and con's but both can be done safely and accurately. I googled your router and it looks like it has a dust collection adapter that attaches to the base that would be on the router when under the table? Put/screw that clear plastic piece that has the dust collection port on it to the base and have it connected to a vacuum. that will help with gathering dust near/under the bit while your above table dust collection can collect the dust from above. That will help with dust collection to a degree. One of the con's to the table method is sometimes/often the dust collects in the groove you are cutting. If you use the plunge router method you have to have dust collection at the bit for any hope of not making a dusty mess.
Routers make a lot of dust and sometimes you just take the piece outside, let her rip and go back in the shop.

 

[Marco]

Let me tell you the truth and maybe annoy some ignorant fanboys of a certain brand.
Plastic "Dust collector adapters" are afterthought devices and are NOT as good as Dewalt or Triton designs.
I had the Hitachi M12V with a AUD90 dust adapter purchased aftersales and installed under the table. One, it blocked some plunge movement. It has to be taken off if I wanted to use template Guides (AKA Guide Bush) or Guide Bush adapter since the screw holes were already occupied. It was not very effective.at removing dust when under the table. OK only when used portable.
So I bought the GMC R2050 2000W clone of Dewalt DW621. With two hosts connected to a Mini-cyclone sucked by a ShopVAC with HEPA filter, my table routing became extremely clean.
It greaved me that I had to take out my M12V from the table just because of Dust collection "defects". So I altered the base of GMC R2050 2000W to be able to accept the sets of guide bushes I already bought for the Hitachi M12V..

Never enclose the router in a box to remove dust. Routers need fresh air sucked in by its own fan to cool the motor or it will burn up,

The Hitach M12V is very accurate router and I still use it to cut Kitchen bench top and sink holes etc and to make jigs and plane slabs.

Plus 1 on the Triton under the table for dust collection

 

[Marco]

I just came across this one

That should work!