King is aiming to reach his fourth sixth tier play-off final - with four different clubs - when Dartford visit Hawks in the National League South play-offs.
He has previously lost in the final with Farnborough, Whitehawk and Welling.
Dartford were sixth bottom when he took over last October, but they won 14 of their 22 regular season games after that to finish sixth.
A 3-0 romp at Slough Town last Sunday earnt them a semi-final trip to Hawks.
Some pundits believe Dartford will have an advantage having played a competitive game - something Hawks have not done since March 14.
‘It might be to the benefit that we have played and they haven’t but I am not so sure,’ King stated.
‘It is going to be on the day. I know all of their players, some used to play for me, they are a seasoned team, good players, match winners.
‘It will be really tough but we have given ourselves a good platform. We go full of confidence.
‘We are strong but this, for me, is the real test because I think they, along with Wealdstone, are the best team in the division.’
Hawks midfielder Andy Drury played under King during his time at Lewes, which included winning the Conference South title in 2007/08.
Drury later joined Stevenage and moved to Championship club Ipswich for £150,000 in 2011.
‘I had Andy with me for years and he went on to have a professional career in the Championship,’ said King. ‘I know they have good players.
‘Roarie Deacon has come back (from injury) and is by all accounts flying, Jonah Aynuga is the joint top scorer in the league.
‘It is going to be a tough, tough ask and their pitch is on a big hill - that could play a part. It’s a game of chess.
‘We know what strengths they have, we have to work on their weaknesses and I have my own thoughts on that and vice versa.’
Drury was one of a raft of players Doswell brought in after being appointed Hawks boss last summer.
He returned to former club Sutton to sign Ross Worner, Josh Taylor, Nicky Bailey, Dean Beckwith, Ayunga and Deacon.
Veteran striker Danny Kedwell and ex-Pompey defender Sam Magri, like Drury, was persuaded to leave Ebbsfleet and step down a level.
Young full-back Benny Read was signed from Wessex League club Horndean, while Simon Walton came from Maidstone.
Defender Craig Robson returned to Hawks in October - he had been a free agent - and in February Doswell brought in another ex-Sutton player, midfielder Bedsente Gomis.
This weekend’s game pits King against Hawks boss Paul Doswell, whose paths first crossed back in 2005/06 when King was at Lewes and Doswell at Eastleigh.
The pair have similar managerial records; indeed, two of the best records in the top two divisions in modern-day non-league football.
‘I respect Doswell a lot,’ King said. ‘I have won the league, he has won the league. He has had cup runs and so have I, so it’s two experienced managers at it.
‘They are a very, very good outfit.’