Can I throw in an alternate that may seem to be a total curve ball?
For best value, I find the ready made commercial sets are pretty low ball on the important things. The reg is often where we look but those are pretty simple things and most all of them do well enough. But when we buy a set, we get a really low quality on the things that bite us most often. The solenoid is not the best as they use a "standard black box" one that uses so much power that it often overheats and that can cause the lube to dry and the metal parts to swell/distort and they stick. The needle valves are like mentioned and really funky to get set right and then they also have a tendency to drift off the setting.
To make my suggestion work, you will need to be able to do some shopping to save money but also be able to screw a few basic parts together. Can do that?
I suggest the metro areas will have place like home brew supplies to walk in and buy a new single stage reg, made for brewing using CO2. That gets you a workable single stage reg, that needs quality parts added to give the long term, stable precision we need. One I often use:
Those parts can come from lots of study and careful shopping or they are also really ready and handy from this site:
Post body kit #1 gives high quality add-on parts that you will be pleased to use and you can get most of it, quick and easy to avoid multiple shipping charges.
If this sounds doable, ask the questions that are certain to be on the mind and there are lots of folks here who can advise on all the little points.
Good to think of alternates or a simple bad idea? Depends on where we each stand! Good luck on either chase!