The Yonex ArcSaber7 is the racquet for you then; excellent maneuverability, good control, and a reasonable amount of power can be generated with it. Good to see that you are also prepaired to get coaching. Try ordering one from Wingeebadminton.com, they have one of the lowest prices for genuine Yonex racquets. The ArcSaber 7 is within your budget there as well: http://www.wingeebadminton.com/index.php?act=viewProd&productId=7
Yes, NS4500 will get you the best performance/price ratio. I also will recommend Cab30ms if you can find one. If you are looking for the best all around racquet, I will say ARC7 is one of the best. However, i still like my Cab30ms better because I am an old timer.
The NS6K isn't that good for 'smashes', it's a super-headlight racquet. Yup, the NS4500 is a good choice as well.
i think the AT900T will be your good friend. head heavy so fits the smashing. ridiculously fast for an armortec again, test them out before you buy