I had my Saito 120 mounted upside down. If I had it to do all over again I would have nothing but a YS 1.10. The YS has its own pressure regulator (pump) internally, with the Saito you are going to have to get a perry pump to be able to put the tank on the CG. Even if you put the tank up front it wont matter, the 100 will fly it great,, it will be just slightly lacking in pullout in a hover compared to what I like,,, but it will do fine.

I had futaba s3001 servos in my u can do and it did just fine.

As far as CG start out at the recommended 4.75 and work from there. I evntually moved my CG back to about 6" to get mine to hover.