For massed 6mm, specifically Baccus, which looks the simpler, with the strongest impact, Napoleonics or SYW?

I'm not quite sure I understand your question?

Are you asking which is simpler to do? Or are you asking which looks better?

My current Napoleonics project - progressing very slowly - is designed to show mass in particular and so uses several hundred figures per infantry battalion. Not sure that really helps you.

My SYW uses the Baccus standard packs with two 60x30 bases per "brigade equivalent."

Both give a great looking game.

Extra Crispy, I don't blame you for not understanding the question; the fault is mine for posing one which is so vague and ultimately subjective.  I suddenly find myself in the position of having to start all over in wargaming and am quite upset over it.  This time I will not let whimsey and ambition overwhelm me in tubs of lead.  I am picking my shots this time, and have come to the conclusion that for a wide range of positive reasons, 6mm is the way to go for most of what I am still willing to attempt.  The new efforts will be radically curtailed in numbers, and real devotion put into the projects which do survive the cut.

The heart of my question goes to the appearance of the armies and the board.

A Horse and Musket endeavor is an absolute must.  I have varying degrees of interest in WSS, GNW, SYW and Napoleonics, and the level of interest is in that order.  At this scale, my concern is that some uniforms are so busy that the massed troops lose their visual impact due to so many tiny spots of color.  I have dabbled with 6mm, and am sold on it, but found the ECW looked bolder and more pleasing than the ACW due to the relative simplicity and resulting elegance.  I am very attracted to one of the matched army packs that has it all - troops, rules, bases, painting instruction, but Napoleonics frankly intimidate me.  Is their mass effect still strong, even with the busier uniforms than SYW or WSS/GNW?

I hope this helps clarify the question.  I'm not sure it does.  Not at my best or most coherent right now and I apologize for that.

Edit to add:  The lead contenders are pairings of either Napoleonic Spanish and French, or of SYW Prussians and Austrians.

Now I understand.

I find that any horse & musket period works very well and looks great en masse in 6mm. The real issue is not the period but unit/army size. Napoleonic uniforms can be simplified quite effectively in 6mm. There's simply no need to paint a lot of the minor detail (I think it make the figures overly busy as you noted).

Here is a shot of one of my "big units" infantry:

Here is a close up of one of the companies. Each company is 4 stands of 3 strips each. So the full battalion is 288 figures:

Here is a cavalry unit:

At the other end of the spectrum, here is a picture of my SYW game, using "Might & Reason" rules. In this game each unit is two bases, each base 60x30mm:

And here is a close up of the action:

My advice would be to go with the SYW. The armies are pretty but not too crazy in their diversity of troop types of uniforms. Some lace but not too much detailing Lots of intersting battles in lots of theaters. Napoleonics requires so many different figures/troops/uniforms it can be hard to stay focused. That said, the Peninsular campaigns are a way to limit that - mostly infantry, limited cavalry.

Your "big units" are truly amazing, and the level of detail looks great.  If I can turn up one of my copies of Final Argument of Kings, SYW mounted on 25mm bases should be about ideal, and those rules always gave a heart pounding game.

Thank you for your thoughtful and thorough answer.  It is very helpful.

Basing on 25mm wide bases (I assume that's what you mean) may be a real pain since the infantry strips are 20mm wide. Unless you like spaces between the ranks you might think about just going with 20mm wide bases and adjust or do an extra stand for each unit.

Molllinary, WSS is actually my favorite of these periods.  I don't see making a big commitment to any period before mid or late March.  I also think the uniforms are perfect for the scale.  Enough color, but not too fiddly.

Extra Crispy, my poor and vague writing strikes again.  I meant to say 25mm scale bases.  IIRC it would allow a battalion of four bases, with each base accomodating three ranks of two strips - 24 men per base to make a total of 96 men per battalion.  The battalion is twice the size of your big companies.  I understand there may be a new edition of Final Argument of Kings coming out as well.  The SYW doesn't hold my interest as much as some other wars in the general period, but I am in love with those rules.

Are you talking about the Johnny Reb adaptation or the Black Powder supplement? Or some other set entirely?

The Johnny Reb adaptation, Final Argument of Kings.  There are rumors drifting around that it might see a revision and republication.  I certainly hope so.  There were times playing that game that I thought my heart would burst from the excitement, and all of the games could have gone either way.  Good times at the SYWA conventions.  Anyway, doing it with 6mm massed armies has nagged at me for a long time.  Now may be the time to do it.