Enewal do a very good dash receiver, I haven’t used myself but saw another plasterer using it , one coat at great thickness, think it’s modified too to go over anything if am correct
And not a bad price per bag
1st scratch scarifier/comb
2nd scratch lightly provide a key with run of a yard brush or dome devil float.
Reason for 2 scratches is to make sure blockwork lines don't show through and weatherproofing.
And no, 1 heavy scratch would not suffice.
Iv seen lads devil float there outside up and come back and dash it. But we have always dashed into a tight receiver coat, though let it pick up a bit. Sometimes pull soft brush through it for grip similar to u would bonding.
Really don't mind it at all. Slightly baffled though by some people who have never let the 2nd scratch dry and then wet dash it. Have always done it this way. Doing a school after Xmas and it's 6mm chip with white sand and white cement. Never dashed with the white sand+cement before. Iv heard horror stories with white cement. Mixing it the same as ordinary sand + cement. I know it's a higher Newton(white cement) so I was going to mix it at 6-1 on top of 1st scratch coat of 4-1(ordinary cement). I'm tempted to try dashing onto wet butter coat but iv always done it onto dry background(dampened down of course prior to dashing)