This is what works for me.
I sweep the day before painting.
I do not sweep or blow off anything off the day of painting, the MDO is lightly sanded and tact ragged down and put aside.
The day of painting I pour water on the floor to keep the dust down.
I use one shot thinned a little bit and add...
I don't know if these guys are a merchant member or not.
But way back when when I stopped hand carving signs I went to them.
And they've been my go to people for carved and sandblasted signs.