I've tried several splitter mounted blade guards as well as overarm blade guard/dust collection hoods over the years and all seemed to have drawbacks so I figured I'd just make my own. After reviewing many shop built/commercial hoods/guards I tried a few experiments by combining features and eventually came up with the following simple design to replace the hood on my Biesemeyer overarm guard to reach my objectives which were..
1. allow easy visibility of blade
2. ability to make narrow cuts without removing (I can rip a little less than 3/4" with a push shoe over the fence).
3. allow use with miter gauge/sleds etc (I made mods to miter gauge/sled fences to accommodate)
4. allow use of splitter on all through cuts
5. excellent dust collection with 2 1/2" hose (4" was too cumbersome)
6. easily lifted/locked in place for blade change/angle check etc
7. easily removed when needed (hose easily slips in/out of fitting and only a couple of twists on lock knob to remove completely)
8. ability to lock into position at specific height (added lock knobs to Biesemeyer support)
9. low height to allow easier use of push sticks
10. easy to replace any damaged parts
Cost was zero since I had some 1/4" Lexan as well as the 2 1/2" fittings hanging around and the rest took just a couple pieces of scrap 12mm multi ply birch (actually I wasted quite a bit of wood on several experiments!). It works very well and dust collection is excellent however a bit of dust gets under the hood as the blade exits the wood at the end of the cut so I'm going to add the "mustache" as seen on a couple of designs online (made from door a door sweep). I also plan to build a new support arm to add a couple of other features I would like to have.