The Irishman carded six birdies on Tuesday to fire an opening score of 66 in England’s North West, with William Harrold alone in second place, a shot clear of a quartet of players in a tie for third.
In the group four shots adrift of McGee is Challenge Tour professional Matt Haines, who enters the week coming off his best performance of the season just a fortnight ago at the Open Blue Green Côtes d'Armor Bretagne where he finished in a tie for fourth.
Haines is a stroke ahead of fellow former European Tour player Tom Whitehouse, who is in a share of seventh alongside 2011 Walker Cup player Paul Cutler.
Former Amateur Champion Alan Dunbar is in a tie for 19th place after an opening round of 73, with 22nd place and ties progressing to Stage Two, to be played in November.
At the other Section B venue, German amateur Sebastian Schwind leads the way on home soil at European Tour Destination Golf & Country Club Fleesensee.
Two eagles in his first 18 holes were the foundation for Schwind’s six under par score, and he leads by a stroke from seven players in a tie for second.
John Hahn is one of those a shot adrift of the leading German, after seven birdies and a couple of dropped shots on Tuesday, as he looks to carry on the form that saw the American make his Major Championship debut at the US Open earlier this year.
There are another two amateurs also going well at Fleesensee, with Denmark’s Mads Soegaard and Martin Keskari both in a tie for ninth at four under par.
It is a particularly congested leaderboard in Germany with 22 players within three strokes of the lead, and those in 24th place and ties set to qualify from the 101 man field.