Actually, your best resources are all to be found on the DVD's of PDF books available from The Emperor's Library link and link
There are two sets, on the first of which you'll find many titles, but two of obvious interest to you are "How Uncle Sam fights or, Modern warfare--how conducted," and the "Full official history of the war with Spain," which should be enough. However, there are another 112 works in this volume alone, and another 113 on the second, including "Wright's official history of the Spanish-American War," and the three volume "The campaign of Santiago de Cuba."
I've bought from the Gentleman who provides the service in the UK, and delivery is reasonably fast, and DVD's are sent post free. Each costs about $15.00 USD, and now there's a single disc edition with all 200+ books for arount $28.00 USD.
I HIGHLY recommend this as your one-stop, lifetime library on the Spanish-American War for less than the price of even one of these in hard-copy.
Best of luck to you!
TVAG
finally dips his toe into the world of Aeronef.
