Blazers are a better choice with the WB rest, they are stiffer and dont tend to get as beat up as most longer vanes do. As far as the POI changing, it always has for me. Couple years ago I did a bunch of testing using various 4", 3" & Blazer vanes from 20 to 100yds. From 20yds to 40yds there wasnt much difference, the 3" & 4" vanes hit the same and Blazers might have been an inch or 2 higher at the most....At ranges past 40yds and out to 100yds is where the largest difference was, the 3" & 4" vanes really started dropping off at those yardages and it almost seemed like the Blazer kept climbing...When shooting at 100yds the Blazer fletched arrows impacted around 12" higher than the 3" & 4" fletched arrows. All the vanes were fletched with a right helical and since the longer vanes are heavier & longer "they end up with more helical on them" they have alot more drag so they end up cutting speed alot faster than the short 2" Blazer vanes.
Another good short vane to try is the AAE MaxHunter, they fletch up really well, and are just a tad longer than the Blazers so you can get a little more helical on them...I've shot the Blazers & MaxHunters alot and had really good luck with both of them with mechanical & fixed blade broadheads...One trick I will mention is if you shoot a big fixed blade broadhead and you have a fletching jig that will do it is to fletch the short vanes in a 4 fletch configuration...You'll loose a little speed with the 4 fletch setup but they steer big broadheads really well.
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