Help In Identifying Stamps

Could one of you really smart stamp guys help me with these stamps

The George Washington I think is # 634 but I don't have a scott's catalogue and I'm not certain because one of the edges isn't perforated.

The mount Rainier could be 750a or 742 but I don't know how to tell the difference.

The next one is of the Bird Antarctic Expedition Not sure if it's 733 or 735a.

Thanks

#742 Mt. Rainer - not #750a which is an imperforate single cut from the souvenir sheet #750.
#733 Byrd Antarctic Expedition - not #735a which is an imperforate single cut from the souvenir sheet #735.

On the 2c Washington, the straight edge just means it is from the edge of the sheet or from a booklet pane. It looks like type I (no heavy hairlines at top of head, but a better scan would help). If the perfs are 11 x 10 1/2, then it is #634 carmine type I.

Yepper-oonie.

Thanks t360

Don't know what I'd do without you.

I did win a scott's catalogue on line and I'm looking for more.

p.s. Just received my perforation thing a ma jig this will be good practice. I'll let you know how I make out.

Diann