Woodcraft makes inserts for wood. https://www.woodcraft.com/products/u...-radius-insert
Penn State has an assortment of small cutters that might be adapted for that lathe https://www.pennstateind.com/store/w...ing-tools.html
I'm not sure which holders would fit the HF Mini Lathe holders but it should be pretty easy to work something out.
If all else fails find yourself inserts that are made for aluminum.