Both are knocking on in years - Hilton is 35, Perry 27 - but both give the lie to being too old for this or that. Hilton packs down in the front row alongside two other sprightly thirtysomethings, Mark Regan and Darren Crompton, their ages totalling 101 years. That century, as Hilton points out, adds up to some invaluable experience in the engine room of the scrum.
"Age is an attitude. There is no substitute for experience in the front row," says Hilton, who won 42 caps with Scotland before retiring from Tests in 2003. "The big thing for me is that I know no one is going to get the better of Ronnie or DC, so I don't have to worry about them. I can just get on with my job."
That job just seems to get tougher. Tomorrow Bristol have to tackle the Guinness Premiership leaders Sale at Edgeley Park. For Perry it is yet another steep step in his rugby education.
"I am not an established Premiership scrum-half," he admitted. "I have only played nine Premiership games - so every game is a big learning curve. I've played against some great opposition and no doubt against Sale this weekend I will learn again there.
"Every scrum-half I've played against has posed a threat, all different: there is Martyn Wood at Bath, Justin Marshall at Leeds and now Sililo Martens at Sale. They are all great players."
Perry looks like he is going to make the grade. His coach Richard Hill says so, and as a former England scrum-half himself he is well qualified to make such a judgement.
"Shaun is an all-round scrum-half," Hill says. "He has all the attributes to make it to the highest level."
Usually by Perry's age a player has either made it or is never going to, but the Midlander, who was tempted south from National League One's Coventry last summer, looks as if he can turn that convention on its head.
"I find everything that is happening to me hard to believe," Perry said. "It is all a bit surreal. Even down to being interviewed by the media. That has never happened to me before. It is not me. My main ambition really is to secure my first-team slot here and to improve as a player, then see what happens after that. If England knocked on the door it is every player's dream to play for their country, but my main ambition is with Bristol."
At least Perry admits life at the top is not easy. In fact he was filled with self-doubt at the start of his Bristol career. "I did not cope well at the beginning," he said. "I was on the phone to my partner every night just whingeing. Moaning that I couldn't cope, that I was going to die, it was killing me.
"It wasn't just the training, it was nutrition. I'd worked in a factory when I was welding and there if you wanted something to eat you got it. Now I have to watch what I eat, watch what I drink, make sure I take in so many calories; it was hard to get used to.
"But my Kimberley said, 'You are staying down there, you are not going to quit'. She has been very supportive."
Perry is going to need support of a different kind tomorrow if he is to help Bristol pull off a shock victory. Hill was not exaggerating when he said: "This is our biggest test of the season to date." Age is not going to matter tomorrow - attitude will.
Premiership team news
* WORCESTER V NORTHAMPTON
Worcester's wing Mark Tucker starts his first game since October. Saints' new signing Robbie Kydd is at inside-centre and Mark Robinson returns at No 9.
* LEEDS V BATH
Leeds' former All Black Justin Marshall returns at scrum-half and Roland de Marigny is at full-back. Bath's Matt Perry returns at full-back after three weeks and Andy Williams is at scrum-half.
* LONDON IRISH V LEICESTER
The Exiles' injury crisis means wholesale changes; the wing Topsy Ojo, 20, makes his Premiership debut. The Tigers' England scrum-half Harry Ellis is on the bench and Brett Deacon is on the blind-side flank.
* SALE V BRISTOL
Sale's Robert Todd replaces Mark Taylor in the centre and the scrum-half Sililo Martens plays. Bristol's centre Rob Higgitt replaces Sam Cox and Manuel Contepomi is on the bench.
* SARACENS V GLOUCESTER
Thomas Castaignède and Simon Raiwalui are back for Saracens. Mike Tindall and Jake Boer have been passed fit and start for Gloucester but the flanker Andy Hazell is out with a head injury.
* WASPS V NEWCASTLE
Wasps' England lock Simon Shaw returns and front-row changes see the prop Peter Bracken joining Jonny Barrett and Alistair McKenzie. The Falcons' England fly-half Jonny Wilkinson is still unfit for duty.
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