Someone in St. Catharines has one of those 91XG's on a 40' tower (in town) and I've heard that they are the best.

Mind you, I'm using a rotary antenna from 1992, that gets everything that the Digiwave gets...only Ihave to use a rotor on it. I've even installed an antenna I salvaged from the early 70's (pointed it towards Buffalo) and coupled it with a CM4228 (Pointed west of Toronto) and they're happy with the 24+ channels they're getting. That house was in Port Dalhousie.

Your TV fool link said you're in Beamsville: I put a Digiwave on a 20' tower in Vineland, on the escarpment...NO AMP, with a rotor, and they got everything except CityTV because they're signal right now is directional, and WNGS (they we're off the air at the time).

I think that if you can get WNGS from Channel 7, you should be able to get 9.

I coudn't find any stores around here that sells the other types of antenna's.
So here is what I'm aiming at, CM4228HD (8 bay), ,CM9521A (rotor), CM7777 (preamp), 100 feet of RG-6 (could cut off the extra to make it more short), CM3412 (distro amp), and 20 feet of RG-6 to the tv.
Is this a good setup?

Yes, I'd think that's a good set up. Directional antenna with rotor and booster. It's what I'd install. You might want to try it without the preamp (CM7777). You might find the distribution amp may be enough.

Let us know how things go.

Use two 4-bays,as high as possible, one aimed at Buffalo and one at the tower. Combo the signals . No rotor needed. This is my setup. I get everything and I don't amp the signal. Downtown Toronto

Does any body know where I can buy a tower to put up the antenna? I prefer something local, like around the St.Catharines area to the Hamilton area.

there is a store in hamilton close to the big steel company and elevated highway . http://nutechelectronics.com/ the say on its web the sell towers. they also have a store in st catherines as per their web.

If I put up a mast, how high does it have to be in order to get the Buffalo stations?

Ideally above roof and tree lines around you and 3m away from any surface. I think Toronto should be your main concern since Canadian TV stations are generally less powered than its US counterparts and probably farther away from you.

I would like some help setting up my antenna.
I had gone out and bought the CM4228HD and I am going to set it up indoors and just temporary set it against a wall until the snow melts, the ground thaws out a bit and it gets a bit more warmer out.
So I got the 4228hd all assembled and I have a short (15 feet) coax (that a Cogeco tech installed) plugged in to it, so if I would like to use the 2 antenna setup (1 pointing north, 1 pointing south-east) and I know I will be risking a 3db loss? with a signal combiner. Do I have to connect the preamp to the 4228hd? or can I run it right to the distro amp and then the signal combiner?
Actually the big question is where do I place the distro amp? After the signal combiner or before?
I made a diagram to show what I am thinking. Hope this helps.
Old Yagi (antenna 2)---------------------\/
4228HD (antenna 1)->Preamp->Coax->Signal Combiner->Distro amp->Tv's?