Junk Silver Or Bullion?

Nothing's wrong with a little diversity to keep things from getting boring. It doesn't have to be either / or. I like a bit of everything!

I personally prefer buying gold coins over bars. I like proof over bullion gold coins, proof eagles, buffalo's, followed by a few proof gold Britannias.

Next in line are semi-numis gold coins, I like gold Pandas and Somalia elephants.

the goal is to have a collection that I can liquidate if I needed too (hopefully that never happens but you never know) while also having a nice varied modern world gold bullion/proof collection.

Yes there is a difference.
The mint does not sell the bullion coins directly to the public. They sell the proof coins to the public.
Proof coins are sold at a premium and the bullion coins are sold by the dealers to the public at a much closer to spot than proof coins.

It may or may not. It depends on the direction of bullion prices. I remember reading articles of how back in 1980, coins that normally sold at a premium like semi key Morgan dollars were being lumped together with common dates to be melted. Looking at an old issue of greysheet in September 2011, the cheapest American gold eagle proof set was bid at $3570 with gold at $1829 giving a premium of about $186 or 5.5%. In July 2016, the same set was bid at $2866 with gold at $1264 giving a premium of about $528 or 22.6%. The same story is the same with junk 90% silver. It is being bought and sold today above the melt value whereas back in September 2011, it was below the melt value. If bullion prices rise significantly, premiums do tend to fall but they do help cushion the blow when bullion prices fall. That is not to say to avoid paying a premium for certain products. I just wouldn't buy them if my only reason was to profit from rising bullion prices. Lower premium bullion like government issued coins, bars, and rounds tend to track bullion prices better.

I might have a bit of an oddball opinion here, but nevertheless, you asked, so here we go:

First of all, I hate the term 'junk silver'. It's still a precious metal and not junk.

Now, try to get clear what you actually want with your precious metal investment. I personally 'invest' a bit in PM, but always via nice looking coins, as I enjoy looking at those and I enjoy the hunt for them. That these coins always will have bullion value next to their face value is a mere bonus. To me, actually, there is no difference between 'junk silver' coins and bullion rounds and bars, as both are made of the same material and their intrinsic metal value doesn't change based on being a coin or a round or a bar. That's also a reason why I like 'junk coins' better: they can also have a beautiful design, where most bars I own are basically just... bars. Rectangle lumps of PM without any design.

Face value amounts are actually not related to the metal value at all. So if I understand your question correctly: there is no magic number 'over the face value amount', simply because those are two completely unrelated parameters. The only time when face value will become relevant again for bullion coins, is when the whole PM market collapses and face value suddenly becomes higher than PM value, given that the currency of your 'junk coin' is still in use, of course. I doubt this will ever happen again, but as my crystal ball broke down, I can't foresee the future anymore.

Now, if you are interested in having PM in any form with the thought of trading it and making a profit: I seriously doubt it will be profitable. Only on a very long run, I guess: the PM market is overheated now, so I expect PM prices to actually drop again when some of the big uncertainties are out of this world (think the US elections, think Brexit, think Erdohan, think Putin, for example). It might actually be more profitable to buy silver on paper than the physical stuff and it might actually be more profitable to invest in certain stock than metals.
What you should keep in mind, though, is your targeted audience: what do you think you can sell the easiest/fastest and what do you expect can be sold with a bit of a premium. That's where I like 'junk silver' best: over here, it appeals to both numismatists and bullion hoarders. Large bars and kilo coins might actually prove hard to sell, if you sell to individuals, as they require a big investment at once, bringing a bigger risk to the buyer than a lot of smaller bars and rounds.

One final thing: ASE is a tad overrated. You shouldn't solely put you money on that. Just diversify a bit.

Back almost 40 years ago when I was a senior in high school I remember the full page ads 'Buying Silver!'
I lusted over fine Morgans in the coin catalogs.

90% was hot then but I remember 40% halves were...dirty.
Roll hunting last few years I piled up the 40's.
Come about 2012 I sold several hundred face 40% Kennedys at almost $4 a pop.
Still have dozens of halves found since then.

@Libertad: Thx for the sharing. Will definitely convey the message to him.

Cheers!