fore& aft placement of tower???

[mykidsdaddy]

Hi,
I am new to wakeboarding and obviously, to these forums. I just bought a tower from a neighbor who owns a Tige. The tower was the one that he got with the boat. He bought a new one for his boat and for $200.00 I now have the older one. I have a 1978 22'6" Kona Mini Day Cruiser. 350 Chevy with a Volvo/Penta out drive. How do I determine the most efficient placement for my new tower? Also, I am think seriously about purchasing a Sevylor Manta Ray Towable for my kids. Has anyone had any good/bad experiences they would like to share? The Manta Ray costs $500.00, I don't want to buy it and find out it isn't what it appears to be.
Thanks to all,
Andy