prepopulating og group ref with id not group name

I had all this working in D6 and now I'm trying to figure out how to make it work for D7.

My use case is that I have a flow to create content from a sidebar drop-down.

Code example:

print $GLOBALS['base_url']; /node/add/discussion?og_group_ref=[]= print custom_get_groupid(); ">Add Discussion

This is what shows in the URL when you select the option:

https://mysitename.com/node/add/discussion?og_group_ref=[]=1175

Problem # 1. The page isn't populating the value of the og_group_ref. It worked for og-id before. My guess is that this doesn't work with numbers.

The resulting URL after inputting the og_group_ref field myself to test the node/add for discussion type, I ended up with :

https://mysitename.com/discussion/work/office-managers-test-group/2427

(URL alias pattern: discussion/[node:field_og_type]/[node:og_group_ref]/[node:nid])

Problem # 2: I would prefer to stick with numbers but there isn't a numeric value for og group ref in the replacement patterns. But if I have no choice, then I assume option value require changing to get og_group_ref or og-group-ref? I am not really clear on the advantages of one over the other. Would og-group-ref would be safer from admins changing the group title?

Please help me understand.