You’d be able to get a rough size by comparing it to one of your other bras.
That's a good idea.
I’ve had one or two of these front-fastening bras over the years. They’re usually terrible.
When I first saw a front fastener, I though, yeah that look better. But then I've never had to use one - so interesting to hear your experiences. I always wondered why bras fasten at the back rather than the front. When I seem women putting on bras, there seems to be one or two techniques Put bra on back to front, fasten at front and twist to correct alignment, and put arm through. Or fasten at back and put arm through.
I still marvel when I see a woman take her bra off under her clothes - it is like watching magician get out of a straightjacket.
Same with strapless bras - so difficult to get one that works well.
They do look uncomfortable - are they better for the bigger or smaller bust?
Everyone has slightly different techniques, but a common way is to put the bra on backwards (hook/eye fasteners at the front, cups pointing downwards at the back) then swivel it around so that the clasps are at the back and the cups at the front - then bring the bra up under your boobs, loop your arms into the straps and lean forward to pop your boobs into the cups - doing what’s now as the scoop and jiggle (where you get your boobs to settle into the cups and then put your hands into the cups and scoop your boobs into place.
Some women can put their bra on cups first and fasten at the back - but I just can’t do it. Although I can take my bra off by reaching back and unhooking it. You get used to it. And yes, we all learn eventually to take our bra off under clothes. It’s a magic trick only females know 😘
As for strapless bras, I’d say they work better with smaller boobs. Although, I have two Curvy Kate Luxe bras and they’re pretty special. Constructed with precision and they work remarkably well. The engineering principles behind bras is that the back band should do about 80% of the supporting, so a well-made strapless bra should (in theory) hold your boobs up reasonably well - but the bigger your boobs, the more support you need with straps - so on a strapless bra, the back band really does have to work hard - when you’re wearing the correct size, it feels really, really tight and restrictive, and your boobs tend to sit lower on your torso (and you end up constantly pulling up the bra all evening). But, when they work well, it means you can wear a nice strapless top or beautiful cocktail dress.
When the evening is over though, boy it’s a relief to get the thing off.