Getting a hat to fit you usually requires a little effort. First thing to determine is your general head shape. There are round, oval, and long oval. Simply measuring your head with a tape may give you an idea of size, but will not guarantee fit., especially since many of the hats on the market are machine made off-shore and not necessarily true to size. IF you have a well made beaver felt, in your size and general shape, you can achieve a good fit with the steaming or wetting methods (Can't vouch for wearing it in the shower, tho' :lol: ). The old cowboys used to take their new hats, dip them in the horse trough or river, and wear them dry. Note this only works well with high quality beaver felt hats. Wool felt (hats, not caps) will just become a mess and not reshape. I have also found that you can usually get a well made hat to stretch to fit if it is slight tight, but if it's too large, you cannot shrink the hat.
Best, of course, is to get a quality hat-maker to custom make one for you. My best fitting hat was made by a hat-maker who uses a 19th Century measuring device that records the exact shape of your head, and creates a template that the hat-maker retains so he can use it for future hats. These are not cheap, however.
As to straws, I have found only palm-leaf ones to endure wetting and/or crushing.