Your perlite size looks perfectly appropriate, I think. A local Hoya friend of mine uses that exact brand, and his Hoyas grow great. I've received a plant or two from him, and it looks good in the mix, too.

If you do insist on having larger particles, consider using coarse Growstone or lava rock as substitution or addition to perlite. But I am not sure there is a need for that.

That's a great idea! Thanks.