New P. Taida Salu 'Sunset" in NZ Spag
 

I recently purchased a beautiful P Taida Salu 'Sunset' from a reputable local grower (he was not around when I got the plant so I had no conversation with him.) When I got home I discovered that the plant was planted in NZ Spag. I is a well grown plant with two flower spikes with many blooms and buds. I love it but I am not happy about the spag. Two problems: 1 - all my other orchids are planted in the same bark, spag, perlite mix that I have been using for 20 years and they respond well to my 5 to 7 day watering schedule. (One time I water in the sink and fertalize while they are still damp, the next time I water in situ with no fertalizer.) A culture sheet was sent with the plant and it said to water lightly once a week and do not over water. I already water a couple of plants (Zygos and a Phrag) more often and hate to have to come up with a third schedule. 2 - I am not really in favor of using spahgnum moss for horticulture as the bogs world wide are being depleted. Bark is a renewable resource. So, will I lose these lovely blooms if I repot now or should I hope that I don't drown or starve the plant if I wait?

You probably will not loose the blooms if you repot but why are you so anxious to do so?
The sphag is already there and "used". If you can see that the roots are doing fine then just enjoy the blooms and repot when they are done.
And even if the plant is "fine" now and begins to have difficulty later then repot at that time.

I repot if I think the plant needs it eminently, if not then I enjoy the blooms and repot afterward.