It was definitely mentioned that Predators were not involved in the shooting of the film in Hawaii. In this case, it is possible that the average sized actors wearing Predator costumes were used as reference points and to help guide the actors. It is also possible that some of the crew members just showed up at the bar in the costumes KNB designed just for the heck of it and are really not playing the Predators.
If you really think about it though, we really will not notice the Predators' size in any sequence other than those that place them in shots that consist of the humans alongside them for size comparison. With a few camera tricks involved, we will not notice the Predators' actual height in POV shots, scenes where the humans aren't in the same shot as the Predator, sequences where the Predator is crouching, running or jumping from tree to tree.
If the Predators are actually played by average sized guys then KNB will have to use scaling techniques such as those used in LOTR to make the humans look smaller or the Predators look bigger. One of the few merits of RR's draft, the Black Predator was described to be 'bigger and impossibly strong' so if the SBP is the same as the 'Black Predator' which is likely then KNB will surely have to use scaling techniques to make the Predator look a lot taller.
It was mentioned that the Predators are going to be inserted through CGI for scenes completed in the Hawaii shoot and this is somewhat of a worrisome factor but I think these scenes are composed of cloaked Predators running or doing incredible jumps alongside POV shots. Considering that the character of Nolan is yet to be cast, they may not have hired any actors to play the Predator yet as well. Hence in this case it would be a good idea to contact RR and have him bring Ian Whyte onboard. Now we all are assuming that Derek Mears is playing the Predator but he himself isn't revealing what part he is playing so for all we know he could be playing the baddie Royce hunts down during the opening.
Anyway, there was some good news present in those articles - the weapons. Royce is definitely going to kick some serious butt with the AA-12 shotgun which is a killer weapon and possibly the most deadly shotgun ever made! Check this out:
http://www.youtube.com/watch?v=p4ebtj1jR7cI don't think Royce will even consider melee combat against a Predator given the bad ass killing machine he has on his hands!
