update readme

README.md

@@ -67,4 +67,9 @@ For generating a specific part:
 `python3 rbuild.py -b yBar --nightly -c micro -t custom`
 
 Generated stls are put into the `stl/` directories. The actual variable values for different profiles can be found in  
-[rack/profiles.scad](config/profiles.scad).
+[rack/profiles.scad](config/profiles.scad).
+
+We recommend you start by printing the `eval_P.stl` file first, just to determine if the default slack/layer height
+configurations work for you. If parts are too tight/loose please take a look at
+[config/slack.scad](config/slack.scad). Please also adjust [config/printing.scad](config/printing.scad) to match your
+slicer settings.

config/printing.scad

@@ -1,2 +1,5 @@
+/*
+  Printer/slicer config
+*/
 
 defaultLayerHeight = 0.3;

config/slack.scad

@@ -8,16 +8,16 @@
 
   Some important details:
     - The general philosophy for slack applications in this project is to subtract space from sockets, while not
-      modifying the plugs. TODO: enforce this
+      modifying the plugs.
     - Values are signed. Positive values can be interpreted as how much to remove from the socket along some dimension.
-    - This shouldn't be used to compensate for more serious part shrinkage (> +-0.5mm differences)
+    - This shouldn't be used to compensate for serious part shrinkage
 */
 
 xySlack = 0.3;
 
 radiusXYSlack = xySlack/2;
 
-zSlack = 0.2; // TODO figure out nice default value for this. keep in mind z shrinkage
+zSlack = 0.2;
 
 overhangSlack = 0.4;