I have a 3.5 SCFM compressor and the lines and filter only take up about 6 cu ft of volume at 3500 psi, and obviously a lot less at low pressure.
Consequently, if filling a tank via stick, it does not take long to have the O2 rich mix flowing through entire sytem to the fill whip if the system is depressurized. But what ever size compressor and filter stack you have, you need to let the compressor run long enough for the stick mixed nitrox displace all the air in the system before you start filling the tank.
Its more efficient to just set things up once and then fill several tanks or a cascade system. 50% is a bit too much for most compressors, so I'd limit the bank to 40%, then top with air (which also lets you get a lot more full fills out of the cascade system before you have to top it off again.) Or if 32% is by far the most popular mix, just fill your bank with it and be done with it.
Even with that consideration, it is whole lot easier than PP blending and avoids the need for a booster to use the vast majority of your O2 in the supply tank. For best results you need to use a proper metering valve for the O2 and if you have one be sure it does not get abused (cranked down tight, etc) if you want it to remain accurate and easy to use.