Pre-33 Double Eagles An Investment Question...or Two

IMO the premium above spot on MS common date $20's is high right now. Been quite while since I added a double eagle to the collection.
Is your purpose to start a double eagle numismatic collection or do you simply want to invest in gold? If you simply want to invest in gold, I would buy 1 oz American eagles instead. Much less premium and you don't have to worry about learning how to select desirable double eagles over less desired ones. Patina is very important to numismatic double eagle collectors.

I would recommend that you look at double eagles that will hold their value, numismatically speaking. Carson City double eagles or other rarer dates and mints immediately pop to mind. Make sure you aim for nice clean looking coins with a rich patina to them. From my experience, I tend to find those more often in PCGS holders, followed by NGC. The common date MS double eagles tend to be championed more by the investment community and of course ride that respective "roller coaster".
For example, a nice looking 1852-O is going to hold its value much, much more than a common date 1928 when gold becomes volatile.
You are correct on your observation of the bimodal aspects of the double eagle market, IMO the first realization a collector needs for this series.
How I handled that uncertainly is I made my collection a mix of rarer dates and common MS doubles. I have a really nice XF 1852-O and little over half of the dates issued by Carson City. Of course, then I got REALLY picky when it came to the common dates...i.e orange peel color...the "European" look as they call it. Most of these coins got their patina from sitting in bags or such in European vaults.
The one that I would hold up as as monument to my pickiness is my 1916-S. Those coins are really hard to find in a lustrous, nicely toned state. Took me 4 years to find one I liked.

I don't have an answer for LOW MS grade common Saints, but I'd be curious to kow everyone's thoughts and analysis as it relates to MID MS grade, both common and not so common (yet not rare), date Saints.

By MID MS grade I mean: MS64 and MS65.

By common I mean: 1908 (no motto), 1922, 1923D or P, 1924, 1925, 1926, 1927 and 1928 (all Philadelphia).

By not so common (yet not rare) date I mean: 1907, 1908 motto, 1909S, 1910D, 1911D, 1912, 1913D, 1914D or S, 1915S, 1916S and 1920P.

Many good comments here. To the OP: Others have advised getting into better dates with more numismatic value (even if they're circulated) and I agree 100% assuming you can afford it. Common dates will almost always be more volatile.

Look into slightly better dates (by mintage/survival numbers) if you can't afford the truly better dates. Also consider MS63 Libs and MS64 Saints unless you can afford to go higher. Lastly, only buy PCGS/NGC certified pieces with good luster and strong eye appeal, pretty coins only with a minimum of bag marks. At 63 and 64 these are available but there's also some dogs out there.

Premiums fluctuate. They sometimes spike when mass-market promoters decide to hype $20s as "safe from government confiscation". Anyone who understands the lust for power inherent in big government and the nature of man knows that's a sales pitch and not a logical statement, as nothing is safe from theft.

Copper value definately doesn't play a roll in the price of early American coppers.

P.S. Sounds like you're considering numismatic/investment type purchases. Have you looked at top tier certified, choice to gem MS silver dollars?

If you don't have any double eagles at all, I would recommend a very nice 1923-D, 1927 or 1928 PCGS MS-65+ or an XF-45 higher mintage Carson City coin. 1923-D is the last common mint marked coin in the series.
Shop around a LOT before you buy it, comparing patina, luster, etc. Make sure there are no copper or carbon spots on the coin. Then give it some time after you buy it. I bet you catch the bug and buy another, and another...

Also buy Q David Bowers guide book on double eagles.

I am in a similar predicament as you. I have been thinking about buying one of the rarer mint marked 1920's double eagles...one of those that suffered greatly from the big gold coin melt in 1937. I just have this fear if I do buy one, multiple bags of that coin will be found in Swiss or French bank vaults...lol.
Their history is unique along with most CC $20 gold that one now encounters. A gentleman by the name of Paul Wittlin scoured Swiss and French banks for rarer mint marked Saints and CC coins and brought them back to the States in the 1940's and 1950's.

I wish I was around in 1932 when the Treasury was offering all the now extremely rare Saints via mail order. I could have bought a few 1927-D's, 1930-S, 1931 and 1932 coins. That would been very good "roll" hunting.

A fun little subset of my DE collection is what I think of as the "Roaring 20's" set. It is 1920, 1922, 1923-D, 1924, 1925, 1926, 1927 and 1928. These are the dates from that decade that are common and affordable, and contains the last affordable mint marked coin. Throw in a nice type coin for the $20 libs and one would have a nice little collection.