[Koha] Add a branch, or not?

[Elaine Bradtke]

We are considering a union catalogue with another small specialist  library
in a different location (170+ miles away).  While it's useful for both
libraries to be able to see what the other holds, most users will want to
prioritize searching their local library.
We are two distinct organizations, so it would be best if each library
could have their own home screen, and a preference set to search for local
items.
What's the best way to do this with Koha?
​Would setting up a branch work, or would it be better to set up a
different instance and somehow get them to link together for broader
searches?
The idea of using branches is appealing as there will be a lot of overlap
between holdings, and it might be easier to link their holdings to our
records instead of converting their database to MARC.​
They will probably both be hosted on the same (remote) server.

Neither library has the budget (or the IT skills) for a
​complicated front end
. If it's a small bit of digital magic that needs doing, we might be able
to beg some help from a friendly IT wizard.

​One more question, will it cause any problems to add a new branch to our
existing Koha setup (16.11)?​

​Any advice will be greatly appreciated.​

-- 
Elaine Bradtke
VWML
English Folk Dance and Song Society | http://www.efdss.org
Cecil Sharp House, 2 Regent's Park Road, London NW1 7AY
Tel    +44 (0) 20 7485 2206 (This number is for the English Folk Dance and
Song Society in London, England. If you wish to phone me personally, send
an e-mail first. I work off site)
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"Writing about music is like dancing about architecture"
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