i think 2 hlg65s would be overkill for veg in that space. 90w would be enough for flower. a single 65W would be fine for veg imho. I've used a 65 in a 2x2x3 and had to dim it most of the time until they were big enough to handle it and by that time I put them into flower anyways.
I think the rectangular shape makes it a good candidate for a couple of 2 ft 24v strips for a 50W total fixture. You could easily build a dimmable tuneable light for under $40 in parts, even cheaper depending on what u have in your junk drawer or garage. Lots of easy options, could run off a 24V wall wart in parallel. just need a couple of wagos. could easily make a frame using angle aluminum, a sheet of metal, or possibly even your T5 housing depending on your DIY skills.
As for strips to use,, personally I love the double row Bridgelux Vestas especially for veg. that would give you a bunch of spectrum options depending how you wire up the 2 channels (2700k + 5000k). u might want the 5000k spectrum for stretchy strains in a 3 ft space. 2 strips would be $20 + shipping. only thing here is you need a 25+V driver. there are some some cheap options available if u choose to go this route.
but using any old 12V or 24V wall wart u have would be super easy and cheap. get some of the clearance Samsung H Influx or V strips for a buck or two each, or even good old EB gen2 strips for $4 each and do the same thing. let us know and we can give u a parts list. I swear it's a super simple DIY (push in connectors, no soldering) and the voltages are safe enough even for first timers.
as a side benefit you will become addicted to building LED fixtures and be able to customize your entire grow
