In the past week they have carried out 'live' training sessions against Swansea University and Llanelli's Premiership side in the build-up to this pre-tournament international fixture.
"We have been training as a finalised squad for a couple of weeks now and we still have a few things to work on but the 'live' training sessions we held against Llanelli and Swansea University were very helpful in terms of giving us some real opposition in order to practice our line-outs, scrums and backs moves in a match-like situation," said Wilson.
"The same goes for our game against Japan on Tuesday evening. There is so much you can do in training but it's only when you play that you can truly assess how things are progressing.
"We will be able to look at the squad, and hopefully most of the players who weren't involved in the Six Nations will be able to play some part in the match. Following the match, we'll be able to take stock of where we are and adapt the rest of our pre-tournament training schedule accordingly.
"Our Junior World Championship Pool opponents Fiji, New Zealand and Samoa will pose different threats to Japan in lots of ways so we want to try and play the style of rugby on Tuesday that we will need to display in those games.
"Having said that, we will need to play what's in front of us and Japan are no mugs. They were finalists in the Junior World Trophy last season, losing to Samoa who have now moved up into the Championship and our Pool."
Wilson believes the standard of training has risen in the past few weeks. "All the players have raised their game with the Junior World Championship now approaching fast. The players who have joined the squad having stayed with the regions during the Six Nations have certainly added a competitive edge to training and everyone is desperate to show what they can do against Japan."
Wales Under 20 Junior World Championship squad
Forwards: Rob Evans (Scarlets), Gareth Thomas (Carmarthen Quins), Kirby Myhill (Scarlets), Jamie Sollis (Dragons), Darran Harris (Blues), WillGriff John (Blues), Samson Lee (Scarlets), Cory Hill (capt, Blues), Matthew Screech (Blues), Rhodri Hughes (Ospreys), Ieuan Jones (Dragons), Ellis Jenkins (Blues), Daniel Thomas (Scarlets), Luke Hamilton (Blues), Dan Baker (Ospreys)
Backs: Jonathan Evans (Dragons), Tom Habberfield (Ospreys), Sam Davies (Ospreys), Matthew Morgan (Ospreys), Owen Williams (Scarlets), Jack Dixon (Dragons), Thomas Pascoe (Blues), Iolo Evans (Scarlets), Luke Morgan (Ospreys), Harry Robinson (Blues), Eli Walker (Ospreys), Tom Prydie (London Wasps), Ross Jones (Ospreys)