I think he's doing a stopped sliding dovetail along the length of a piece of pressure treated 4x4 that's been ripped to 3x3.
@wizardgmb, does the dovetailed groove run all the way through both ends, or is one end still solid wood?
You can slap together a shop made one in a few minutes with your table saw. (feel free to message me if you're not sure how to make one). It's worth doing - it will help stabilize the work piece and make the operation safer.
Definitely remove as much of the waste as you can with your dado stack or a straight router bit, so you lessen the work the dovetail bit has to do. That will let the wood react however it is going to when you're using a straight bit, rather than a more trapped dovetail bit.
I've been in the store a few times Steve.. Frankly, I have a hard time supporting a store that has 99% crap with a couple diamonds in the rough. It might cost me a little more at a store genuinely trying to carry quality stuff but, I'd rather see that store stay in business so, is worth a little extra.
I recently bought the Bosch JS572EBL, which is one model up from the 470 you were looking at and I love it. It's a bit pricier but still $100 less than the Festool and you don't need an addition $200 accessory kit to get the tilt base.
The only thing I've had to compare it to is a very cheap Skil jigsaw and the difference is night and day. I have medium-large hands and love the barrel grip. The cut is amazingly clean and plumb and the saw is very easy to control.
I enjoy inlay work, too. If you find that you like doing inlay consider this..... I really like a plunge router for inlay work. It is nice to position the router and plunge the bit straight down especially when working with small areas. It is also nice to just release the lock and have the router bit raise itself out of the work. This reduces the chances of gouging the edge of your routed area when lifting the router and a plunge router lets you just set the router right side up on the workbench.
Holly stays white under waterbournes. Some can impart the faintest cool tint but a base coat of super blonde shellac will counteract that. I use M L Campbell products but I have heard good things about General Finishes waterbourne finishes.
Not that I think your primo wood needs any but the water based stains General makes have behaved quite well for me. Easy to handle and no smells plus reasonable prices.