The Mini honestly does not care a fig if you use HP, MP or LP it's all the same to its built in regulator which regulates whatever tank input goes in, down to 200psi or less.
You can use tri-flow on your bottle and asa thread to aid taking your tank off when the mini is gassed up, dry firing deffo helps. I do know people use oil in the ASA side to aid threading the tank, it has been said before that 800psi isn't enough to combust oil, however 3000/4500 will readily heat lube or oil to a combustible level and with that much air under pressure it would make for an extremely dangerous piece of home brew pyro... (to re-iterate the point that should be made, do not put oil or lube near the tank fill nipple, this will put oil into your tank the next time it fills, oil and HPA equals diesel engine. The first three letters of diesel give the result away)
But I used to have a mini and had the thread saver on/off in the reg, helps a great deal...
With all the upgrades it had, I managed to get the operating pressure down as low as 150psi and still used a tank with a 650psi (mid pres) output, it makes little difference...