Personally I'd use 2 links per spot if you can.

With one link linking to a deep page of your site, and one link pointing to your home page.

That way you get the best of both worlds.

If you don't have that option, then IMO I'd switch it up a little bit. Or at least turn your keyword into longer tail keywords for your anchor text, so it's not just your keyword all by itself and you get some variety in there.

I believe that "variety" in anchor text backlinks per say has an larger impact than the same 3 words over and over and over.

I also think that linking to home page only is not the best.
Optimize each deep page for one keyword is better option.

You can go as deep as you want. But you want to link to pages you want to acheive better serps for.

If you link to a specific product but don't believe that specific page will rank anywhere, then you're wasting your time.

But if that product is very well laid out with descriptions and optimized, and you're trying to rank for that "product" with that page, then yes link to it.

Def do deep linking, but do it strategically. You always want to mix your links up, it's much more natural. What site has 'only' links to it's home page? Not many =)

From your home page put links to 4 or 5 of your main inner pages.
From these inner pages link back to your home page
From your other pages link back to the 4-5 pages
Then backlink the buggery out of the other pages.

It is a simple pyramidal structure

homepage
page1 page2 page3 page4

subpages 1,2,3 link back to page1
subpages 4,5,6, link back to page2
subpages 7,8,9,10 link back to page3

No need to link back to your home page or the 4-5 pages because when google checks your backlink it will simply follow the links all the way back to your homepage (which should be indexed and ranking already)
Of course these are all intext links, not put in a navigation menu in a sidebar.

When backlinking I use the 60/30/10 rule

60% of my backlinks are my keyword phrase
30% are a derivative of it
10% is the actual URL