Two different beers one way to carb

I will be doing a wheat beer. What I have is 3.8 Vols CO2 at 45 degrees. That would put myline pressuer at 30 psi.
I will alsobe doing a Kolsch, for this 2.6 Vols at 45 16 psi line pressure.
I do not have a two way. My line is split off on one line.
Can I hit the wheat up to 30 psi every few days until its carbed, then dispense as normal.
I usually leave the line at 15-16 psi for a week and then down to pouring range after that. So i am not worried about the Kolsch.
Or will the wheat be just as good with the 15-16 psi for a week?

Definitely recommend investing in a dual reg if you intend to be serving two different beers at the same time...

That said, I would keep your Kolsch at 16 PSI, as well as the other at 16 PSI (since it's one reg). Every couple days, or after serving the other, I would turn off/disconnect the Kolsch and hit the other with 30PSI. The 30PSI will be maintained (assuming it's properly carbed) until you serve, but you definitely want to keep up the carbonation by hitting it with 30 PSI on occasion. If you let it sit as 16 PSI too long, the CO2 will drop out of solution and give your horrible foam, so keep hitting it when you can....

Not too bad on occasion, but again, it might be worth upgrading. Micromatic sells a threaded nipple for joining two primary regs; Keep an eye out on CL for a used soda one or invest in one your next online purchase.

If you want to serve the wheat beer at 3.8 vol you will need to hit it with 30 psi until its carb'd, bleed off pressure, serve at 15, and then re hit it with 30 when your done. If left for long periods on 15 psi it will eventually regulate itself back to that, but you won't be able to serve it at 30 psi through your same length of hose.

Personally, I would just put it at the same carb level as my other beers. I have a dual tap regulator, but I use one for carb and one for serve. I am not about to try and re-balance lines for every different beer I want to serve.

I got the answer..... Bottles, SWMBO wants to bring it to Texas when we meet up with her sister.

Bottle conditioning makes all the sense in the world for high carbonation. Try https://www.homebrewtalk.com/f13/priming-keg-bottle-conditioning-92692/