Historic Map rant

I've been working my way through the literature on the Battle of Antietam lately. I've recently finished reading Murfin (The Gleam Of Bayonets: The Battle Of Antietam And Robert E. Lee's Maryland Campaign, September, 1862), Tom Clemen's edition of Carman (MARYLAND CAMPAIGN OF SEPTEMBER 1862, THE: Volume 1, South Mountain), and am working my way through Harsh (Confederate Tide Rising: Robert E. Lee and the Making of Southern Strategy, 1861-1862, Taken at the Flood: Robert E. Lee and Confederate Strategy in the Maryland Campaign of 1862). I will shortly be going back and rereading Sears (Landscape Turned Red: The Battle of Antietam). One thing that has become very clear is that I need to see some better maps, in particular of the fighting in the morning on the north end of the battlefield. What happened there is very confusing today, and was quite evidently equally confusing while it was happening.
I anticipate that the maps in Clemen's second volume of the Carman manuscript will be excellent, but that book is still probably a couple of years away. However, there is a famous set of maps from the early 1900s, the Cope maps, which were prepared at the same time that Ezra Carman was writing his account of the battle. The Cope maps are no secret, they are a sequence corresponding to various times of day. A poster of the 8:20am-8:40am map is even available at the Antietam Battlefield Visitor Center (and yes, I have a copy of that one.) But seemingly, unless an old copy shows up at an antiquarian book seller, the full set is unobtainable these days (The maps in The Gleam of Bayonets are based on the Cope maps, but the reduction to a size suitable for a trade paperback didn't do them much good.)
So in the course of searching, I found digitized copies of the Cope maps at the Library of Congress Site. Unfortunately, the web based viewer provided is an archaic design, crude to the point of uselessness. The good news seemed to be that you can download them, but wait, they're in a proprietary compressed format named MrSID, based on research at Los Alamos but commercialized by an outfit named LizardTech. The howtos hint at Mac OS X viewers, but no such viewers appear to exist.
I am profoundly aggravated that resources like these, which should be free and easy to access, are instead so damned difficult to get at. The only good news in all of this is that I do have a copy of Parallels on my Mac, but i shouldn't have to run windows at all to get reasonable access to these maps, producted by the US Government more than 100 years ago.