Keeping in mind that a small reflector is NOT going to get you a throwy light...
Here's the link to the five-degree optic: http://www.ebay.com/itm/110819715928
I've used these 10-degree optics from FastTech: https://www.fasttech.com/products/1606/10007055/1574902
...and they will fit the EDC-sized hosts like the Convoys, sometimes with a little bit of shaving around the plastic holder.
Another alternative: I got surprisingly good results making a P60 Aspheric thrower from a 501a/b light:
https://budgetlightforum.com/t/-/6296
I won the lens lottery and ended up with a good optic, and started with a known-good high-bin emitter that is overdriven slightly. This light is optimized for throw, and is thowier than a similar S-type host due to the larger lens, but is still easily outthrown by C8-type lights. It's still a lot of fun though due to the small size and can be handy. If you can find an appropriate optic for the Convoy S-lights, a dedicated thrower with an overdriven XP-G2 would be a fun project...
The Nanjg 101AK is a good driver for low-powered EDC lights but is limited to 1400mA so you wouldn't get maximum brightness which will be essential for maximum throw. Stick with the 2.8A Qlite if you want bright...
Also, keep in mind any of these Qlite/Nanjg drivers won't work with two cells in series; they are for single-cell or parallel use only.