With tech diving comes depth and a requirement for reliable equipment. What you can get away with as a recreational diver might cause you a lot of grief as a tech diver. As a tech diver, risks increase along with depth and increased bottom time, so you have to ensure what you get will perform as your diving grows, and I can see that's what you are trying to achieve.
A light failure at 10 metres might cause some angst, however you may get a lot of ambient light, sufficient to either continue or be able to safely abort the dive. At say 70m in dirty water, light levels are very low so your gear needs to work or it could be very dark indeed. Also remember much of the tech gear has been developed or designed for cave diving where risks are high and things must work to plan, as compared to recreational gear which can be as simple as a cheap non dive torch that seals to 20m ok.
My personal opinion is you increase risks if you try and do tech diving on the cheap. That's to say "cheap and poor quality" gear (or gear being used past its design point), rather than just cheap but good quality gear. If you take a casing rated to 60m down to 60m you are pushing the envelope and would need to be assured that you have assembled the casing perfectly so it wont leak. Taking a 300m casing down to 60m tends to not stress the better rated casing as much so "hopefully" you get away with less than ideal assembly. I took an Intova camera to 60m (rated at 60m) on my first dive on the HMS Repulse and watched it drown and die in the first 3 min, needless to say I had no pictures of a dive I had been wanting to do for a few years. I now have a GoPro 3+ mounted in a 200m rated casing. Whilst its not a super doper camera, it meets my needs and is a bit over designed for depth, but I am now confident.
You have 40 dives, I would suggest you spend money in becoming a better diver so you better approach your goal of becoming a tech diver. In the mean time you will experience a lot and see what everyone else is using as your experience grows, and then make a better decision about what you actually need. I have a big box with stuff in it I was sure I needed, only to find out many were mere trinkets.
If your current light works fine, hold off a bit, however if you are really busting to get a good one, or your current light sucks, do a lot of homework on cost vs quality, and then see what others in your area as tech divers use and try and get something you feel you can afford but will be useful for a number of years. I have medium quality lights currently (that were cheap but reliable)and am also looking at a quality dive light (perhaps a Hollis) but am waiting for a special before I spend in the vicinity of $500. My current lights work ok so I am not in a rush, although I would love to get a canister light too.
I also need a new wing and have my heart set on a Hollis SM-100 but again they sell for some $1000 and I have a wing (all be it single bladder and simple design), which is in good condition but was cheap to buy and met my needs at the time and still works fine. I however now should use a twin bladder so will upgrade soon.
One of my mistakes was to buy gear in anticipation of doing a course (caused by being ripped off for rental gear on my first tech course, as I paid $300 for rental of a wing and tanks for 4 dives, but failed to ask the rental price until after the fact and when the bill was due). I bought price wisely but (in hindsight) should have waited until after certification and completing some dives.