R583B is not normally active, I'd guess somewhere in the vicinity of 10% of the time (Mon-Fri). As bladeangle advised, over the top at 10K would work fine, and that airspace does not belong to WLM but BN Centre. As the area is used at the request of the WLM flying SQNs, it could be used anytime based on their current training/retraining needs. Best bet is to check NOTAMS for codes WMX, WEX and WWX anytime after Friday for the coming week, so you catch (mostly) all of the planned use of the restricted areas for the week ahead.