Re: Making a load box/hotplate?
Hell I say go the old fashion way and mic the speaker cab.. but find a quiet way to do it. Plus, you know you can do the pull 2 tubes trick right? I do it with my 6505+ all the time. It does make a difference.
Finding the "quiet way" can be rather difficult

. Its no secret that tube amps "open up" as you turn 'em up. The pull 2 tubes trick only does so much. Attenuators can be helpful, but can also muddy up your tone. It can be especially difficult if you have a noise-sensitive neighbor.
Then of course there can be problems with room acoustics...having a nice, sound-treated room to record in can make a world of difference. Obtaining such a room for recording can be problematic for a home studio, though

.
Not to mention microphone choice and placement. That, and if you're recording in the same room that your amp is in, monitoring can be difficult without some nice isolation cans.
Add to that how much more effort it takes as opposed to DI. The list goes on and on...honestly.
In the end...it all depends on what your situation is. I record in a small studio, and I have very noise-sensitive neighbors (namely, my parents).
You can get great-sounding recordings both ways. My argument is simply that DI is an easier, more cost-effective choice for the home studio.