PRW Platinum Rockers, Trick Flow Heads, 408: Anyone Else Use the Same?
Yeah .030" of side play will make some noise. Couple that with a fast hughes hydraulic cam and you have clackity-clack... You can tighten the side play up to .015-.020 per pair of rockers. I shoot for .015" clearance, and usually end up with .016-.018 by the time things are tightened and mostly centered (side to side) on the valve tips. In addition to shims, the hold-downs have a bit of 'wiggle room' when tightening them down so you can also use that movement to help get your desired clearance. You can usually get what you need without ever having two shims right next to each other. It's kinda tedious and can require starting over a few times to get them all close to the same, but you'll get the feel for it. Start at one end and methodically work your way down.
And just be prepared, performance setups like yours are never 'quiet' even if they are hydraulics. I bet it runs like a beast though!