I can't comment about these speakers specifically, but can endorse the idea of 8" speakers for acoustic guitar and vocals; there's no reason to use anything bigger unless you add instruments which require more low end than is produced by a guitar or by vocals. I have been very satisfied with EV ZxA1 units used for FOH and as monitors. They weigh only 19 lbs each.
https://www.electrovoice.com/product.php?id=1004