Or is there a better time?

of what I have read here...anytime is good time to cut staves....

Salvatore is right. Just be sure to seal the ends with something. If not, your stave could check on the ends within hours.

Would furniture laquer work?

i am not sure about that. I use elmer s glue works good for me.

"The best time to prune is when the knife is sharp." Goes for harvesting osage too, the best time is whenever you can. I like to seal the ends with shellac. Spray can about $4, fast drying, see through (so you can admire the rings) and works fine over sap.

Go to it!

Cut when you can.  I prefer late winter but have been known to cut in August too.  Shellac is the cheapest sealer.  Cut the canned version by at least half with denatured alcohol.  2-3 quick coats should do it.

Get Dean Torges "Hunting the Osage Bow" If you don't have this one classic work, you're cutting yourself short on lots and lots of answers to the questions that will come up.  After you cut and split, need to debark, get rid of the white sap wood and coat the WHOLE stave with shellac, or it WILL check. THEN you can relax for a while:)