Does the Makita have a laser or other light? I just got a Hitachi 10" slider with the fixed sliding bars. If I plug it into my Fein Turbo II in auto mode the vac turns on as soon as the saw is plugged in. I guess the power supply for the laser/LED light draws enough power even when off to turn the vac on. The dust collection isn't perfect but it's better than I was expecting. Sliding compound miter saws are notorious for difficult dust collection. I did make one worthwhile discovery rigging this up. I have 2 hoses joined with a coupling. That makes it easy to disconnect and reconnect the dust collection. I have the vac in a semi-fixed location and it's convenient to separate the two hoses when I'm not using the saw. I had an old black stiff shop vac hose but needed another 10'. Did a little checking around and wound up with a 10' length of clear PVC hose from Peachtree via Amazon. The stuff is great, very flexible and no 'memory' so it'll lay wherever I put it. I hooked it up, put my hand over the end and turned the vac on. It sucks together from 10' to maybe a foot but maintains its diameter, no restriction to speak of.
https://www.amazon.com/CLEAR-COLLECT...s%2C148&sr=8-4
I did have to get a couple screw-on tapered ends. The threaded portion works, I just had to trim the PVC away between the wire coils in order to get it to thread. It holds so far and if it doesn't there's always hose clamps.
https://www.amazon.com/Shop-Vac-Vacu...s%2C155&sr=8-2