p,
There are 3/4" adapters slip/male thread. Glue at desired elevation on riser. Teflon tape and thread on 3/4" threaded cap.

or 3/4" adapter slip/female thread. Glue at desired elevation on riser. Teflon tale short threaded nipple and thread into female adapter the thread on 3/4" threaded cap.

When ready to fit drip connection remove cap and adapter down to 1/2". I would check out the drip system you want to go with and see what connections they will require before making the above decisions. JMHO Aloha

Thanks for the reply.

I looked at the available dripline, dripper and sprikler head attachments and connectors, (on spriklerwarehouse.com), there are some 3/4" female thread, more 1/2" male thread, and lots of 1/2" female thread options.

What would a reasonable standard be, e.g. if a pro irrigation installer did the job, how would the pro have done it?

P.

concur with lehua, use 3/4" female thread adapter. you can then easily bush that down to to 1/2" if needed.

Ok, thank you.