I pronounce them differently. [name]Caspar[/name] “caz-par”, [name]Caspar[/name] & [name]Gaspar[/name] are almost indistinguishable. [name]Casper[/name] is softer “cass-purr” and is what people are more familiar with so regardless of how you spell it you’ll still get “[name]Casper[/name]”. If that’s the sound you like, then I’d say [name]Caspar[/name] looks better but it’s more likely to be misspelled
I’m a [name]Casper[/name] fan ('though I like [name]Jasper[/name] too), I love the nativity tradition of it be a ‘magi’ name over the jewel and Twilight associations of [name]Jasper[/name]. It’s a little rarer too which I like.
Prefer it spelt [name]Caspar[/name] though I know its like the ghost.