I often just pot the moss up into a larger pot and fill around it with new potting mix. If you are afraid that the moss will hold too much moisture you can let the excess fall away and just keep what is attached to the roots.
Do you have a Hoya mix with bark or coconut husk chips you use or is your mix mainly soil and perlite or something similar?

Mike

I've been transitioning all my hoyas and other aroids to a mix of equal parts crushed granite, fine pine bark, pearlite, and regular potting soil. I haven't had any of them in the mix long enough to tell if they like it but based on what I've read, they should.

I have a few Hoyas in a mix that is very similar and they do well but I have to watch carefully or they dry right out. My Hoya loyceandrewsiana is in a mix like that and I can't tell you how many times it has dried out and the growing tip died back. The crushed granite/grit really seems to create fast drainage. I have to water at least twice a week when the weather is hot and sunny or the plants just don't grow.

Mike

Oh, is THAT what causes the growing tip to die? Well! Now I know I'm not watering enough. Thanks! I had no idea what was causing that. I will be very careful from now on.

It all depends on what Hoya it is but some don't like to dry out and they will let you know if they get too dry. Hoya loyceandrewsiana is a pretty succulent species but that does not seem to like to be constantly moist but mine at least does not like to dry out too much or for long either while it is in active growth.
Some Hoyas seem to grow OK but they will not flower if you keep them too dry while others will abort new leaves if they don't get watered often enough.

Mike

And all the pubicalyx cultivars I grow are real water guzzlers. Once they're happily rooted and growing, they grow FAST and dry out FAST. I got my 'Red Buttons' in 2007 and it's already in an 8" pot - I bet you're going to see a LOT of new growth this year!

Denise in Omaha