Hi, mine was recently around 23MB but after a good tidy and rationalisation I brought it down to just under 18MB - I have under 2000 tiddlers, my larger tiddlers are entire 4 to 8 page scanned chapters from books.
My tidy efforts were due to the perception that my increasingly sluggish Tiddlywiki was suffering a size issue, I thought my research was in danger of being size capped on performance issues.
Finally I started playing around with the performance instrumentation and achieved some large and easy wins performance wise. I had a custom tab on the right hand side of my page - it goes all the way back to when I first started with Tiddlywiki - filters used there were the performance culprit and fixing them as much as I am able at this time has delivered massive performance benefits.
My laptop is pretty fast but my android phone and tablet would not sell for much in a second hand shop - in addition I am using Tiddloid with RCX simple server ( so I can play locally stored videos ). I recently had a big slow down on android that I thought was due to me adding more and more embedded videos* - no foundation for my thinking just a vague feeling that somewhere between videos-RCX server and tiddloid I had crossed some kind of threshold - but No!!! when I made the changes mentioned above my android devices sped up dramatically as well. Just goes to show that hunches and guesses with performance are not always reliable.
( *video stored in a local directory on the same device which is the reason I use RCX server on Android )
I am now under the impression that size is not performance issue for me right now, my attention is more focused on filters. I changed the order of statements in my slowest filter with good results by following advice on the tiddler named “Performance” on https://tiddlywiki.com/
My next step is to look at replacing the wikify gadget.
Currently my worst filter performance wise is one that shows the most “important” 100 tiddlers ( 100 is an optional number controlled by a slider ) based on the number of backlinks so that filter has to count the number of backlinks for every tiddler. I have it in mind to find solutions but the big wins gained so far mean I feel I can comfortably treat performance as an ongoing issue rather than a panic.