I've seen this question asked on other forums. My opinion is old threads are an important part of the forums - there is often wisdom and experience that may not come to light until someone takes the effort to search. Some information may be dated but some is valuable and as timely as it was when originally posted. I think replying to an old thread can be a useful way to bring it to the foreground.
If a person is not interested in either an old thread or a new thread, they can simply skip it and go on. Others certainly may be interested.
As for the pressure vs vacuum, I have no experience with dyes but do have some with getting epoxy deep into spaces (in this case, between plates of metal). We always used vacuum. Submerged the objects and applied vacuum until the bubbles stopped. I never tried this with wood so I don't know if pressure would be better, especially with dye.
I do know that in the lab, vacuum was considered much safer than pressure. An implosion might cause destruction of the vessel and limit damage to the vessel and contents but it was more likely the first crack or seal breached would allow air to enter and mitigate the hazard.. An explosion from pressure can throw shards everywhere. We we needed to use pressure and also observe the experiment, we had special chambers made with thick Lexan windows (up to 2" thick). Of course all this is a matter of scale - both the pressures and volumes involved.
For moderate vacuums we often just used a plastic half dome sealed to a flat surface.
If using pressure, I wonder if a stovetop pressure cooker with a over-pressure relief valve might work.
JKJ