When it comes to compeitions, they are ALL ABOUT CONSISTENCY. Most competitive Chinese shooters, including myself, stick to lighter set-ups with light ammos (6.4-8mm), I reckon the idea behind is to maximize stability by having more control over your pull and release. I personally shoot 7mm with 0.4 18-10 150mm cut. People should adjust according to the actual performance. Generally, with 6.4-9mm steels balls, the popular tapers are 17-9, 18-10, 1911, 2012 for anything below 0.6. Though I have seen elite medium/long-pull shooters in competitions, but due to the lack of anchor point references it usually takes a longer time to develope consistent shooting with medium/long pulls. Instead, short-pulls is relatively more effective for compeitions. It is the most popular style for competitive shooting for a major reason - solid anchor points (usually on faces). Certainly it differs from personal preferences, short-pull with light set-up further maximizes the consistency per shot with miminal time put into practice.