Hi Cruzin
getting a foil kite is not always the answer in low winds, especially if you're not into racing or getting the best upwind angle possible.
I have lots of experience hydro foiling in sub 10 knots winds with both types of kites and the foil kite is clearly no advantage for me unless you buy like a 18m or 21 and want to tackle the sub 7 knots winds... Foil kites collapse and invert easily in very low winds and it's very hard to recover from that, most of the time you will be swimming in with a kite gradually filling in with tons of water. Foil kites (especially race specific foil kites) are also more fragile and demand more maintenance and more frequent bridle replacements.
Longer and thinner lines are key in my experience to expand your wind range. My biggest kite is a 12m CoreXR4 and in sub 10 knots I will systematically use a custom made 35m lines bar with thin race lines. For example, with that setup yesterday I was hydrofoiling at Melville between 1 and 2pm, wind was 10 knots at the highest and the kite wasn't stalling at all. Plenty of power and a super fun session. Other hydrofoilers would typically pull out their 18m foil kites in those winds, but there is no need for me.
If you simply used your current 10m kite with longer lines you would increase bottom end for hydrofoiling by 2-3 knots easy. Make those race lines and increase your bottom end by another 2 knots.
So at your weight, on your 10m kite with 30m (or more) thin race lines and some skills you should be able to hydrofoil down to a minimum of 10 knots easily. Below that would be a bit difficult.
Christian