Ruby is in Lalbagh Fort road, coming from Urvashi theater towards Lalbagh, take right towards Minerva circle & it is on the right hand side, rewinding may cost up to 1000rs, I had paid about 850 or 900rs about couple of yrs back. Be very specific if you want to run up to 90/100W so that they will use full potential & CBZ's Magneto is very good & can generate such power, ATB dude
You can go for Gypsy Reflector on Pulsar cap's & that would suffice & you can use up to 90/100W on that set up.
Coming to using 55/60W on stock battery - You see the headlight in CBZ is AC type & thus on stock condition we cannot expect to power 55/60W, you will have to go for Coil rewidning & can run up to 90/100W, if you are from bangalore then head to Ruby electricals & get done the coil rewiding, another option is to make your bike DC & plonk 55/60W but that would need bigger battery & RR change etc to keep your battery charging better & help to run 55/60W.
I had the first option done on my CBZ & it was very good compared to stock & a much safer one too..