Isles, who caught the eye across the Pond after making the switch from sprinting to Sevens, joined up with the Warriors this season in a bid to embark on a career in XVs.
He is yet to appear in the RaboDirect PRO12 - where Gregor Townsend's men will contest a home semi-final against Munster on Friday - but Seymour has been impressed with the impact he has made in training.
"Carlin is an unbelievable athlete, he's the quickest guy I've ever seen, his speed and his prowess is pretty well documented," said Seymour.
"He's learning the game and he's keen to learn and he's developing his skill-set and his knowledge of the game.
"Guys have tried to help him as much as possible but he's keen to learn which always helps. He's not come in and tried to do everything on his own back, he's taken on board everyone's help and advice and fingers crossed he can have a successful XVs career."
The RaboDirect PRO12 playoffs are building to an exciting conclusion and you can get involved - buy your tickets to Glasgow Warriors v Munster at https://www.eticketing.co.uk/scottishrugby/details/event.aspx?itemref=359
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland