Wow, thanks for the welcome to the board, and also for the advice... really interesting opinions.
My unorthodox technique was probably best explained by mentioning I would not complete a full racquet drop from the 'trophy pose' position, therefore I was swinging my arm around more to meet the ball rather than bringing my racquet from behind my back. I believe this would result in less power, and certainly less spin too. With my 'new' service technique, I am moving from the trophy pose to racquet drop to throwing of the arm slightly better, but it needs work. It's the bringing the racquet down my back which I find tricky, maybe I need to do some specific drills that integrate this positioning. Interestingly pawan89, you mentioned low balls toss.... so true, it is too low (I hit as the ball reaches the peak), that is another thing that needs to be developed. With my toss as it is, my complete service motion from transfer of weight on feet all the way to follow through, is fluent, but in a way I feel rushed. If I am to improve, I believe a higher toss may result in me staying in trophy pose a fraction longer, thus allowing me to bend my knees more then power from knees upwards. Fingers crossed!
Comfort wise, the eastern backhand does feel good to me. I use a single handed backhand with an eastern backhand, sometimes varying to towards an extreme (almost western backhand) when bounce is high and I'm feeling lucky, so I am accustomed to holding the racquet in this way. Therefore, this grip makes sense and doesn't seem unnatural/ uncomfortable.
Funnily enough dmastous, you mentioned the eastern forehand grip - with my older serve I occasionally switched to this when hitting first serves with more pace. And guess what, Boris Becker was my inspiration for playing tennis! The grip worked, but if I remember correctly I stood a little more open to the court. I even did the Becker 'back and forth' motion before serving for a while! I don't think I'll be going back to it anytime soon though.
If I was to prioritise what I want from my serve, I would definitely say spin and placement over power, with just one grip (to avoid telegraphing to my opponent as much as possible.) So it is good to know that both these grips enable slice, top and kick. Maybe for now I'll continue with the eastern backhand and see how it develops, try and form a fluid serving motion with a better balanced and timed trophy phase. Since each grip offers options though, hopefully in time I will experiment with each.
Thanks again, and hopefully there are things I will be able to share with others on the forum. Having returned to tennis recently, I have dived head first into studying the technique of shots, footwork, the mental game, and court strategy in order to improve my game, as well as a little on the science of racquets. It's all good fun but I'm becoming addicted!