Matt - sorry for the delay. To respond to your points above:

a) Wilco - as is says in the project description "Since the customer selection restriction facility will not be required by multi-site practices who use a non-restricted customer pool, a 'Use Location Customers' switch will be added to the Practice. If this is unchecked (the default) then the 'All Locations' checkbox on the customer selection window will be checked; if checked, then the All Locations' checkbox on the customer selection window will be unchecked."

b) add locations to users with none. When I did the work on our system, we already had different account types for the housecall (CC) and street (EIAH) practices. Below is what I used simplified to set all customers with no practice location set to some standard practice location.

/* get locations */
select * from entities pl where pl.arch_short_name = 'party.organisationLocation';

/* from above output, get entity_id of required practice location */

/* set Customer location for all active customers with none */
/* NOTE - replace 165 in the following with the entity_id or the practice location to be used */
insert into entity_links (version,linkId,arch_short_name,arch_version,name,description,sequence,source_id,target_id)
select 
    0,
    UUID(),
    'entityLink.customerLocation',
    '1.0',
    'Customer Location',
    'Customer Location',
    0,
    e.entity_id,
    165
from entities e
left join entity_links el on el.source_id = e.entity_id and el.arch_short_name = 'entityLink.customerLocation'
where e.arch_short_name = 'party.customerperson'
and e.active = 1
and isnull(el.id);

Hope this helps.

Regards, Tim G