After discussing in great detail with Matt (Hummel Aircraft), I thought this would be a good place to post a couple thoughts about building the HB.
If you are considering building a HB, from my experience, there are a couple questions you need to ask yourself.
1) Will I fit? If you are 5'9" and less than 170#, Probably.
2) Do I have the skill and confidence to fly my HB when complete? The HB is a very quick, Morry preferred responsive, aircraft. If someone asks, I have always recommended training in an RV4 or Pitts to get proficient.
If the answer to either is no, look at the H5 as a better option.
If both are a yes, I would recommend the following:
Get familiar with the plans. Fabricated parts are limited for the HB since we have never developed a complete kit. Hummel Aircraft can provide any welded parts, wing ribs, bulkheads, hardware, canopy, and maybe raw sheet metal, extrusions, and tubing. I say "maybe" because there is a very small demand for Hummelbird parts and it is difficult to afford to keep a lot of inventory on the shelf.
In comparison to most all metal homebuilts, the HB, in Morry's words, "is built like a tank". That said, the only change I would recommend is making bulkheads B, C, and D from .025 6061 rather than the .040. The firewall can be as thin of steel or stainless steel as you like. (galvanized ductwork material works great). We had furnished builders with .025 bulkheads for the last couple years.
Also the shock gear has little value for the complexity and weight.
I would really encourage prospective HB builders to consider the H5. The only advantage the HB has is miles per gallon, period. (But as a fat guy, I may be a little prejudiced).