The last-chance qualifier for PDC Tour Card Holders saw 93 hopefuls in action at Wigan's Robin Park Tennis Centre as they battled for precious Grand Slam spots.
Bunting and Webster raced through qualification to book spots in the £450,000 tournament at the Aldersley Leisure Village from November 10-18 alongside four Grand Slam debutants.
Former Lakeside champion Bunting defeated Dawson Murschell, Tony Newell and Rowby-John Rodriguez to secure his third Grand Slam appearance.
Three-time Wolverhampton quarter-finalist Webster edged out World Matchplay semi-finalist Jeffrey de Zwaan 5-4 in their decider to ensure his return to the event, after also seeing off Mario Robbe and Matthew Edgar.
Former World Youth champion Keegan Brown, a quarter-finalist in the 2014 Grand Slam of Darts, will make his third Wolverhampton appearance after wins over Lee Bryant, Brendan Dolan, Darren Johnson and Steve Lennon.
Bolton's Joe Murnan qualified for a second successive year after winning 5-4 in his four games, defeating Ritchie Edhouse, Prakash Jiwa, Luke Humphries and Tytus Kanik on the day.
Former UK Open quarter-finalist Steve Hine secured his debut in the event by defeating John Goldie, Kevin Burness, Scott Taylor and Arron Monk.
Andrew Gilding sealed his Grand Slam debut with a narrow 5-4 win over Alan Norris, having only dropped four legs in his earlier defeats of Ricky Evans, Adrian Lewis and Alan Tabern.
German youngster Martin Schindler completed a memorable day in Wigan by following up his earlier qualification for the PDC Unicorn World Youth Championship final by securing a Grand Slam debut.
Schindler won in a deciding leg against both Simon Stevenson and Jamie Lewis before defeating Jan Dekker 5-3 to seal his spot in Wolverhampton.
Somerset's Ryan Searle will be another debutant in Wolverhampton, after edging out Australia's Kyle Anderson 5-4 in their decider, to follow up wins over Mark Wilson, Sven Groen and Darren Webster.
There was disappointment for world number five Daryl Gurney as he lost out to Dekker, while former finalists Robert Thornton and Dave Chisnall and two-time semi-finalist Adrian Lewis also missed out.
The bwin Grand Slam of Darts will be held from November 10-18 and broadcast live on Sky Sports.
Last 32
Jan Dekker 5-2 Stephen Burton
Martin Schindler 5-4 Jamie Lewis
Stephen Bunting 5-2 Tony Newell
Rowby-John Rodriguez 5-3 Chris Dobey
Andrew Gilding 5-2 Alan Tabern
Alan Norris 5-2 Davy Van Baelen
Arron Monk 5-4 Wayne Jones
Steve Hine 5-1 Scott Taylor
Jeffrey de Zwaan 5-2 Dave Chisnall
Mark Webster 5-1 Matthew Edgar
Joe Murnan 5-4 Luke Humphries
Tytus Kanik 5-1 Dirk van Duijvenbode
Keegan Brown 5-2 Darren Johnson
Steve Lennon 5-3 John Henderson
Ryan Searle 5-3 Darren Webster
Kyle Anderson 5-2 Robert Thornton
Last 16
Martin Schindler 5-3 Jan Dekker
Stephen Bunting 5-0 Rowby-John Rodriguez
Andrew Gilding 5-4 Alan Norris
Steve Hine 5-3 Arron Monk
Mark Webster 5-4 Jeffrey de Zwaan
Joe Murnan 5-4 Tytus Kanik
Keegan Brown 5-3 Steve Lennon
Ryan Searle 5-4 Kyle Anderson