It's a good design. You will need a router to cut out the form. You can make one with hand tools, but it is a whole lot easier if you have a band saw. An oscillating spindle sander is the first power tool I would buy after a band saw. You should get a random orbital sander too as they are...
Do a search on eBay for zinc sterate powder. It is cheap and it is the same stuff as smoke in a bottle, windicator, etc. $20 worth will last a lifetime. Also, get a snuff/coke spoon to transfer it into your bottles.
I have one. It serves a purpose, but for a Merino vest that is thick and warm you can't beat the L.L. Bean commando v neck vest. Very thick, 100% merino, and $59 with free shipping.