I have absolutely no experience in designing a system, but I'm an appraiser in the collision repair industry at a shop that handles a number of high-end cars, so I've seen and worked on many of the systems...both OEM and aftermarket add-ons. So I totally understand how they function if nothing else.
I assumed your bulb would have that small cap integrated with the tip of the bulb...again not what I'm talking about. Even most newer halogens have something like that. However, an HID glare cap is usually quite large...maybe 3x the diameter of the bulb, and ALL of the glass of the HID bulb is completely hidden from view, not just the tip. I guess my point is, I've never seen an HID system where you could actually see any part of the bulb after it was installed...and I think that's key.
Most people I've talked to who have installed the bulb you picture in their halogen-designed car headlamps have started to run into trouble with the law around here (Indianapolis area) The police have been cracking down on the non-DOT approved conversion systems because they are becoming much more common, and definitely are causing temporary night-blindness for oncoming drivers. Not sure if the rest of the country is following suit yet or not.
Anytime a car comes into the shop I work at for collision work (assuming headlight was damaged in accident)...the shop is not permitted to re-install the non-DOT systems. We must either restore the entire headlamp system back to halogens, or ask the customer to pay for a proper reflector housing assembly (usually $500 to $1,000 or more if available for their particular vehicle) that is DOT approved to make the system legal to return to the customer. Failure to do one or the other opens the shop up to liability for accidents, and we got a notice from somewhere (I can't remember if it was the state? I think so.) that threatened $10,000 fine if the shop was ever found to have installed a non-DOT system in a car.
Of course usually the customer doesn't want to pay that much for a true and proper DOT conversion. So we usually return it to halogen and then hand the customer all their surviving leftover control boxes/ignitors/bulbs, etc in a box, and then I'm sure the customer goes home and re-converts to the HID bulbs on their own after they buy the damaged pieces they needed. But at least it takes the shop out of the liability equation.
Slightly off topic...but the other hot thing around here is people stealing OEM HID headlamps out of cars...just like the good old days when people would break in to steal stereos. Many of the HID headlamps in Acura's, etc cost more than $1,000 EACH. And some clear the $2,000 mark...again EACH. So it's very attractive for a theif to yank one and resell it. A relatively common insurance claim around here: "both headlights were stolen." The rest of the car is usually undamaged unless they had to pry the hood open to get access. I even know of a moron that lives near a friend of mine who actually did jail time for a string of headlight thefts he finally got busted for.
I doubt I can really help much at all...sounds like you've got the whole electronics thing pretty well figured out. Like I say, just test-run it as an oncoming vehicle before you go for long night-time trail rides an see what you would think if that light was coming at you on the trail. Compare with a sled that still has stock headlights. It might be perfectly fine...every headlight design is different so maybe your SX will handle the HID glare OK. And for now at least I doubt you need to worry about the legalities of the lamps on a snowmobile like we do on cars.
I'd recommend you do some Google searches on the topic: "aftermarket HID cutoff" "HID glare cap", "HID glare" or "HID cutoff". There's a ton of discussion out there from the compact tuner group on their experiences with controlling or not controlling the light that spills from these conversions.
Here's one with some nice pics and good discussion:
http://www.srtforums.com/forums/f12...een-aftermarket-hid-kit-oem-hid-retro-203383/
And a cool video (not from the US, but still good) that explains the situation:
http://www.autoexpress.co.uk/videos/featuresvideos/204742/xenon_test.html
Good luck!