You know this doesn't have to be complicated. An ounce of tobacco will take 80 mls of pg on average and you should get 60-70 mls of concentrate from that. You can get a quality juice that taste just as good or in many cases better than vendor bought juice. There's a NET being sold for $1.00 per ml that you can make yourself for pennies and it will be identical.
Hot or cold whichever method you choose will turn out fine, and you can filter through a coffee filter or cotton in a syringe. Filter it as many times as you think is enough. Start at 20% ratio of concentrate to base and take it from there.
I'm not there yet with the filtering being as good as say MVJ, I'm going to try one of those SS syringes stuffed with 5 micron media felt. But MVJ must be using smaller filters and a pressurized feed. Hard to duplicate at home.