You're going to need to pitch your buddies a lot more aggressively than that.
You've worked closely with Mike in the past at ExampleCorp, where he was one of the team's top contributors. He was great at code reviewing, a calm and reliable voice during production incidents, and always ready to help out new graduates. Mike was the guy people turned to with their most difficult WidgetStack bugs, fixing problems that had stumped other developers. He would be a great asset to the company, and a great fit for this role - which you note needs WidgetStack. He has your strongest possible recommendation.
You're going to need to pitch your buddies a lot more aggressively than that.
You've worked closely with Mike in the past at ExampleCorp, where he was one of the team's top contributors. He was great at code reviewing, a calm and reliable voice during production incidents, and always ready to help out new graduates. Mike was the guy people turned to with their most difficult WidgetStack bugs, fixing problems that had stumped other developers. He would be a great asset to the company, and a great fit for this role - which you note needs WidgetStack. He has your strongest possible recommendation.
The thing is - the pitch also has to be true.