Building the Audio Note Kit 1 SET amp...

If it were me I'd go for the larger woofer and higher efficiency to best hedge my bet against clipping. Clipping is always public enemy # 1 of good sound. Its the kryptonite to the amps Superman. Goal # 1 should be to keep it out of the picture. The one is in the best position to assess improvements from tweaks like other tubes, power cords, etc.

At least that's how I would look at it.

Charles,
The one I think you're referring to is the S-Lore, which uses more conventional "hi-fi" drivers (from Seas, I think, hence the "S") rather than that Eminence pro-audio wide-ranger and the Audax super tweeter. My gut would be to go for maximum efficiency and a few extra Hz of low end, therefore the Lore.
It's remarkable that you can scour the Internet for Tekton reviews and you'd have a very difficult time finding anyone who has bad things to say. The only gripes I could find via Google were
1) A few folks who suffered production delays and long wait times a few years ago when the company was smaller and,
2) A bunch of guys on the Parts Express speaker DIY forum who were snickering over pictures of a disassembled Lore, griping about insufficient cabinet bracing and damping, as in, "I could build a better speaker for less money." But even among that tough crowd, several people who had actually HEARD the Tektons admitted that they were amazing for the price.
I am currently using a cannibalized computer power cord with the Kit 1 and yes, someone else said a better cord would be an improvement, so I'll look into one of the high-value Pangea cords from Audio Advisor. Better 300B's will have to wait awhile from a financial standpoint, but I know that Grant Fidelity, for example, offers discounts to ANK customers on the higher end Chinese tubes, so I might look into that. I've also heard that there are the "super" 300B's by KR and Emission Labs that put out some extra power somehow, but I'm not sure if they're compatible with my amp. Anyway, that's all for down the road.
This speaker thing is ultimately going to be a tough call. Much of what I like sounds so great on my De Capo's with the Kit 1, save for the limitations I've already noted. I am awfully curious, though, how the Kit 1 would perform with a very efficient speaker that gave it lots of breathing room.
Charles, now I "get" the SET thing... it's amazing. There's nothing subtle about the improvement in my system and the pleasure this amp is providing.

Mapman,
Yes, agreed.

The thing about Tekton is that they offer a very good value and a favorable customer satisfaction policy. Plus the choices are highly limited when one needs a good high efficiency speaker on a limited budget. It seems there are only a relative few ponds one can fish in for inexpensive yet proven high efficiency speakers these days compared to the competition.

Its all about what floats ones boat. The good news is there is always a way to make it all work out. More so these days than ever.

Hi Rebbi,
Unless there's some unknown sonic penalty I'd choose the larger more efficient Lore just you and Mapman. Reading various reviews people are genuinely impressed by its sound quality, no easy feat at that price point. I seems to be much more than a budget speaker that can play rock at high SPL. It's said to do justice for jazz and classical in terms of tonality, nuance and sophistication, now that is encouraging. Very curious to read your thoughts once you've heard Sebrof's Tekton. I hope it all works out for you.

If it were me, I'd also go for the higher efficiency Lore. IF I was changing speakers.