Questions:
1. Can I use the PA120 in the future with the DI-1D without getting a separate PA-SD and instead just use the existing AD-SD stand?
Technically, you can. JBC now offers an adapter part # CHB-A, that allows you to attach the T245 or T210 etc..directly to the DI-1D without requiring the AD-SD stand.
https://www.jbctools.com/chb-a-converter-product-1209-category-9-menu-1.htmlThey don't have such an adapter for the "MicroTweezers" PA120 at the moment, but obviously, you could build one yourself, if you figure out the wiring.
The mechanical form factor differences between the straight handpiece T245 and the Microtweezers PA120, however, makes it difficult to use the AD-SD stand for resting the PA120 down. You'll have to find some other DIY method for putting the PA120 down.
I don't like the PA-SD stand, because JBC went the cheap route and used grey "conductive paint" instead of the same nice piece of silver color metal surface they used in the AD-SD stand. And both stands are the same price.
JBC put a lot of pride and work into the T245/AD-SD as it's their flagship product. So, that's a really nice tool. But the MicroTweezers is an afterthought. There are many things about the PA120 that suggests improvements are likely coming down the line in the future.
The PA120 does work though.
2. Does anyone know if the DIT-1D comes with CL8499 (newer) or or CL9885 (older) cleaner? JBC's website shows CL8499
I can't say what you'll get, if ordering from Tequipment.net. You'll have to check with them. I had a similar concern when I ordered my unit from Janelonline. At that time Janel was showing the DIT-1B pic and I wanted the latest DIT-1D, so I requested verification from Janel, and they assured me I'd get the latest, which I got. Janel doesn't stock these units anymore, which I believe is because JBC has been making too many changes too quickly to this particular product, so if you order this unit from Janel you'll always get the latest, because it will immediately be a backorder.
3. Are there any other benefits of going for either the DI-1D or DDE-1B? In particular, is having two tools really useful? Or any other standout features to make DDE-1B worth the premium?
I like the DIT-1D because it's a smaller unit, and takes up less space on my workbench.
However, it delivers a max of 130 Watts to the T245 handpiece, while the DDE-1B delivers a max of 150 Watts per tool on each channel.
Not that I ever needed that extra 20 Watts, just a fact to be aware of.
Also, I have lots of tools hooked up on the same mains circuit, so the DIT-1D helps to keep by total wattage down, which is another consideration.
There's always some balancing act in getting these tools.
4. What do people think in general?
I'm currently leaning towards DI-1D since it seems to offer the best compromise in terms of my needs today and what I would realistically use in the future.
You'll definitely be happy with the DI-1D. The bigger brother DDE-1B only adds marginal functionality, at the cost of grabbing a lot more benchspace, chewing up more mains power, and you only have two hands, one to hold the tool and one to hold the component, anyway. Whatever you plug into your DI-1D will fire up in a few "seconds", so there's no long warm up time to worry about in switching tools, by pluging out and plugging in another tool.
But, hey, it's all about personal preference.