To get a rabbit to use a leash, the first thing to do is select the right leash for this type of pet. Depending on the type of rabbit, the animal may be more fragile than a typical cat or a dog. Rabbits, being prey animals, are also more likely to panic and try to run away. Therefore, to protect the rabbit from injuring itself, a harness would be best.
Rabbit Agility - About Harnesses
Petsmart should have some rabbit harnesses in the rabbit aisle. You can try a vest one, but I would make sure it has buckles on the neck and chest and the velcro is not really the best after a while as fur gets stuck to it. They are not my favourite, but better than some other choices.
There are many types of harnesses that people use on their rabbits
The link you posted doesn't work, so I don't know the exactharness. I did look at the rabbit harnesses on that site, and thetop one is probably not the best one to use. It looks like it isrope and probably adjusts on the rabbit. The adjusting can causechoking if you pull on it and the rope can cut in.
H-Style Rabbit Harness | Rabbit Hopping
The best idea would be to buy a 'Kitten' harness,as I would of thought most adult dog or cat harnesses will be way too big! Some Miniature puppy breed harnesses are also useful,these can go REALLY small believe me! I have a rabbit & kitten harness,for 2 of my bunnies they both are very good. The ones I use are like a figure of '8' a loop the safely fits around the neck & a loop that fits around their waist. Both loops have clips,as buckles are often difficult to remove in an emergency. Do not just buy a collar,it HAS to be a 2 'looped' one to prevent injury.Search for keyword: small animal and bird rabbit collar and lead Sanko co., Ltd. best rabbit harness mesh No. 795 Leave colors and patterns and other rabbit_herness usa_shirabe0308 on the day of flight