Tall Squat-ers - please share your tips

So I've been doing ICF 5x5 for just over a month, and am struggling with squats- I'm 5'8 with long femurs compared to the rest of my legs - torso is about 3/4 length of my legs. At best, I can do 1/2 squats - I do a 15 min warm up - breaking a sweat b4 lifting and do hip&ankle stretches to open up. I ve reached about 60lbs on squat but have scaled back to 40lbs to work on my form and at least get to parallel - I have the common problem most tall ppl face which is my torso leans all the way forward when I squat down - almost to my quads when I'm at my fullest ROM? To any tall squatters out there that have manage to overcome this and squat deeper could you please share your tips? Posted a similar q in my "order of exercise" post and I have tried box squatting and front squats to no avail - still only manage to get down to 1/2 a squat - the only thing that seems to help a bit is a wider stance/sumo squats - which makes me think it's a mobility issue based on research I've done? Doesn't help I have a bad knee however been trying to focus on pushing my knees outward when I squat and this seems to help me avoid any stress/ twinges.
- is it a matter of time to build up ROM and strength? Any suggestions welcomed .