Originally Posted by imrf
...Thoughts? My iron goes to 900...
You never usually have to set the soldering iron higher than 650°F to get a good solder joint, unless the only tip you have is too small for the joint.
A setting of 600°F should be hot enough for most connections.
Setting it to 900°F will just burn off the flux too fast and actually help create a cold solder joint.
Most lead-free solders solidify to a matte (non-shiny) finish, so you can't use that criteria to judge a solder joint as being cold or not.
Did the solder want to wet up the wire as you soldered it (good solder joint), or dimple down and not want to wet the wire at all? (cold solder joint)
Note: I've assumed the PCB pads and wire were clean and free of grease/oils before you soldered them, because they have to be clean before a good joint can be made.
If the parts were clean and the solder wetted both parts readily you can assume they're good joints, but good joints can still fail later if the solder is also being used to physically hold heavy components in place.
Make sure all bulky parts are secured with black zip ties or glue before soldering them to the crossover PCB, however, small resistors won't physically stress the solder joints so they don't need to be secured.