We use Calendly all the time (and love it) and usually present it as 'grab a time that suits you' (or words to that effect). I think that makes it sound like please choose what you'd like , rather than please fill in this form and maybe I'll speak to you . I think that also allows you to avoid the 'or just send me some times that suit you', which I try to avoid because it just ends up in several rounds of diary tenni…
I like that language. I'll have to try that.