Quick, probably dumb questions from a transmission novice

So I think I already know the answer, but since this is the first time I've gone inside an automatic trans beyond a fluid and filter change, I want to be sure I do it correctly. I have a 904 that is leaking fluid around the shift lever rod. I have the new seal and it would appear at first glance that the valve body needs to come out in order to remove the old seal from the case. The service manual is not super specific about any of this. It just says "remove the seal from the case with a punch". But then it says you can remove the seal with a small screwdriver from the outside. I don't want to damage the case or the shaft by doing it the "easy way".

So my questions are: 1) Should I remove the valve body or just try to get the seal out with a screwdriver? and 2) If I do remove the valve body, do I then need to replace gasket(s)? I would assume the answer to 2 is yes, but then do I need a full valve body seal kit, or is there a single gasket for just removing and reinstalling the valve body?

Thanks in advance for helping out the dumb guy.
Remove the valve body.
It is not very difficult in a Mopar 904 or 727 and no check balls fall out. It is fairly difficult to get the old seal out while the transmission is in the car and valve body is still in place. Not much room to work above it. You already have to remove the throttle/kickdown lever and the shift lever and once those are off it only takes a few minutes to remove the valve body. Plus, if the valve body is out you can clean off the area where the seal rides.
Here is a video Cope did a while back for another member here. This is how easy it is once the valve body is out.