I would suggest the SCLCR (RH) or SCLCL (LH) tool holders that use CCMT 22.51 or 22.52 inserts. These are diamond shaped positive rake inserts like the above so they have only two usable tips. This holder has a 5 degree clearance angle in front and on the cutting side so you can turn and face with the same tool with the shank of the tool perpendicular to the work.
Very importantly, the same tool holder also takes CCGT inserts for aluminum with an aggressive positive rake. These inserts approach HSS in sharpness and cutting ability - they are NOT better than HSS in aluminum but they are close. A CCGT 22.52 will produce a mirror finish in 6061-T6 and will last practically forever. Note that the last digit in the insert designation is the nose radius; a 22.51 is ~1/64" and a 22.52 is ~1/32". Both will give a nice finish, albeit with different feed rates. The holder and inserts are readily available on ebay in sizes that will work on your lathe.
I would suggest a 3/8 holder/bar if using an AXA post. Some companies make 3/8" holders that take the larger 32.5X inserts but they may cost more and the performance of the larger, and possibly more expensive, inserts isn't worth it. I own holders made by Seco, Iscar and ToolMex (Bison?) and all work very well. Chinese knock offs are plentiful on ebay but I cannot attest to the accuracy of the insert pocket as I don't own one.
Inserts for this bar are available in grades and with nose radii to cut almost any machinable material. The cost for the bar and inserts is not unreasonable and they work very well, indeed. They do not outperform HSS on a smaller lathe but if you prefer not to grind tools then this is the one I would go for.