Hold on your making much more of this than it needs to be.
There is no reason for a generator to leak oil. There are thousands of generators out there and they don't leak.
First it's probably NOT your generator itself leaking but the gasket that seals it to the accessory case. Replacing the generator with an alternator with not make this problem go away.
There are lots of threads about this particular gasket on this forum. The gasket seals not only the generator but also the tack drive. Lots of mechanics think they can use a short cut and cut the gasket and only replace that portion of the gasket under the generator.
What they don't realize is there is a hole through the accessory case that the oil pump gear shaft rides in and it is very close to the gasket edge in between the tach housing and the generator. There can be a leak without splitting the gasket. Splitting the gasket almost guarantees a leak.
So ask the mechanic who installed the generator how he did it.
As for the seal in the generator it needs to be installed upside down from what you think. In other words when your looking at it installed you will see the back side of the seal. Remember oil pressure is outside the generator trying to get into it not in the generator trying to get out. Rebuilders know this and chances are they did it right but since your going to have to remove the generator you should check it.
It's also been documented here that even using a new uncut gasket the type made of thick paper will not guarantee a leak free seal even when combined with gasket sealer. Some have suggested that a gasket be cut from 1/16" thick rubberized cork gasket sheet (available from NAPA) and Permatex No. 2.
Here is a link to another thread on the same subject.
http://cessna170.org/phpBB2/viewtopic.p ... sc&start=0
Oil was everywhere...... 
all the way from the cowl to the tailwheel. I cleaned it up and went to check on the plane today and there is another puddle under the engine....the oil is comming from the GEN Worse than before 
I am going to call Aerotec an see if I can get a credit on the GEN and install a Alt kit.....anybody have a ballpark price on this and would this be better than the Gen on the plane? Hope this will fix the problem.....Frustrating having oil leaking after an engine overhaul 