First - Welcome, folks here look forward to helping on the Vintage AS '27 - researching problems using the search function can be overwhelming when 100's of responses need to be filtered through but alot of the writing talent are still active here for clarifications...
Sorry I don't know where to refer you too for heavy duty manual.. I got my '73 manual from .ca ebay vendor - letter sized paper makes diagrams hard to read, especially the micro print gets a little blurry on numeric lists, etc. Look for legal or ledger sized paper - If I see a reprint done on larger paper I'll buy twice since the first manual was impulse purchase...
Tambour is the name of the flexible roll-up doors, is the paper backing coming apart? Applying cloth-type theatrical duct tape as a backing can patch things up, sometimes for years. Some types of the early 70's tambour don't age as well as others - My dark wood finish has had all the overhead replaced, the others have dried out and are almost too brittle to mess with.
There is alot of posts on tambours for suppliers - use the search, luke!