Aftershock- why would you pre-exhaust the quads with isolation before the most beneficial lift he can do? i would prefer to squat with a different method and work all the effected muscle groups fully.
As many people have said already, barbell hack squats are a great thing to do if you are struggling to do back squats, you wont be able to lift as much weight with them so it might buy you some time before you move gym. Front squats can be worth while (as long as you can clean a weight effective enough for your chosen training method). Try unilateral bulgarian squats if you fancy a challenge, great for evening out imbalances if you have any.
Bottom line is, you cant do the most effective lift there is, dont sacrifice it. I was in your position, trained at a leisure centre gym (max 30kg dumbells) and whined about not being able to strength train. I worked there and could train for free, i decided to travel half an hour to a club a lot further away, pay for its use and its the best decision i have done in my lifting career. If you want real progress, train somewhere else
