Well, and my question is: how is that any proper way to read a book?
If the trick is that you can't read more than one or a few poems at a time without negatively impacting your enjoyment/understanding/recall of them, singly and as a group, then it stands to wonder why anyone writes or publishes books of collected poems at all. I'd wager it's because the book is the traditional vessel to convey money from readers to writers and so poetry has unfortunately been pushed towards that format despite that 50-75 pages (enough to warrant a volume) is really far too much poetry to send out, or process, at once.
I do think lit mags are the best way to absorb poems. Better than books and chaps at any rate, for the most part. The lit mags are much easier to read, the many different writers featured within offer variety and a certain amount of discontinued freedom to the content which prevents readers from being overcome by the emotional monotony of poetry. But if you are reading lit mags you are already really putting yourself out there and doing work to be involved in the literary community; they aren't money makers for publishing houses.
I think we agree that poems are like very rich bon-bons and enjoyed best spaced out hours or days apart from each other. If that's the case however it really begs the question, "why present poetry in books?" aka "how present poetry for enjoyable/successful mass media consumption in any way?"
As for my experience with poetry books, I can read through one in an afternoon. I like to take a fair bit of time between poems especially weighty ones and more time at the end of a book to digest. But that, in my mind, makes poetry books really bad entertainment, if half the time I spend with it I have to close it on my lap and toss over in my mind everything the poems show me that I'm trying to process - if I have to spend an hour thinking about a movie to figure it out, it's just a bad movie.
Anyway, just rambling ranting.