John will be keen not to replicate last year's finale at Twickenham where they arrived on the back of a successful Scottish tournament only to stumble in London where they failed to make the main knockout stages on day two. As a consequence they slipped to eight position in the overall series standings.
With a top five place at stake this weekend, Wales have called upon the vast experience of Richie Pugh along with Neath flying machine Dafydd Howells.
Former Wales Under 20 wing Iolo Evans also joins the squad along with Pontypridd's Owen Jenkins and Jersey's Nicky Griffiths.
Wales face New Zealand, who have an unassailable lead at the top of the points table, Canada and Kenya in their pool tomorrow.
Paul John's men bowed out at the semi-final stage against the Kiwis at the Emirates Airline Glasgow 7s - but only after letting slip a 14-7 halftime lead. New Zealand will be missing dangermen Kurt Baker and Belgium Tuatagaloa through injury so Wales may be sniffing a chance of a rare victory against the men in black.
"The boys did really well last week in Scotland. Every one of them put in a huge performance. I couldn't fault the commitment and effort they put in. We were down to nine fit players in the last couple of games due to injuries.
"We've got a tough pool this weekend. New Zealand are series champions for a reason while Kenya and Canada both pose major threats. Canada made the quarter-finals of the main draw last week and they will be looking for revenge against us as we were fortunate enough to get through to the semis after a hard fought game.
"Hopefully the boys can finish the campaign on an encouraging note as we head towards the defence of our World Cup crwon."
Wales 7s squad for the Marriott London Sevens
Craig Price, James Davies, Adam Thomas (capt), Richie Pugh, Iolo Evans, Nicky Griffiths, Lee Williams, Alex Walker, Adam Warren, Owen Jenkins, Dafydd Howells, Chris Knight.