You can cram all the HTML/JS/CSS into 1M and still have room for more code than you would ever need. Use grunt to combine and gzip all of your assets, including images. Though you wouldn't be able to do OTA updates then.
I would use the extra memory to enable calls to https services. I am thinking particularly of google location APIs...
I have been working on three designs at the same time with the Wemos. Two are multiplexed, and the third is an IN-18 direct drive clock using 2 x HV5530 (or HV5562, but I have 5530 in stock). I have to say, it is a real relief to use the HV drivers, they make life really easy.
My designs are these:
1) Direct Drive IN-18: I am very likely to open source both the hardware and the software on this one as an experiment. I would like to see what happens when may people can improve the design. I'm interested to see if it develops into something where many people offer it, but the orders go to the people who provide the best support, or whether it just dissolves into a free for all where everyone loses in a race to the bottom.
2) IV-3A/IV-6 VFD driver board: This uses an low cost multiplexed way to drive VFDs using only Opto-Isolators. I have everything ready to release this one. It will not be open-sourced.
VFDs are a bit tricky to drive like this: It would have been much easier to use a direct driver.
3) A 4-Digit Nixie for IN-12 or IN-2 mini clock using a 2 board design and multiplexing. This is fairly traditional, but I intend to sell it with tubes to see if that helps the sales. I also designed a 3-D printed case for it which is really cute.
In short, I'm loving the Wemos, and probably won't do anything other than that for the near future!
It looks like you have an LED directly under the nipple on the IN-18 board. With the IN-18 I have in my one tube clock right now, the nipple goes all the way down to slightly below the board, even though I am using those D-SUB style pins which hold the tube quite high.
Also intrigued by: I see a USB connector on the VFD board, but not on the others. What is that for?