That ratio can be what you want it to be. You will need to determine the strength and the volume of the product that you want and work it up or down odor strength wise to meet your needs.
Start with the base volume that you want, then begin adding your essence until it seems good for your needs. Shake well after each active dose is added.
Ideally the best way to get this done most effectively is to do this over a period of a few days. If not, your nose will get odor blasted and subsequent odor samplings will not be accurate due to odor saturation of your senses and the area being worked.
You will need to get away from the mixing site by leaving the area for a while to clear your odor receptors after each amount of skunk is added. Once your receptors have cleared to a degree get back to it and sample it once again.
Once you have recorded your volume of base then record your volume of essence added as best you can. This way once you have worked up a desirable / acceptable batch you can easily mix it again without guessing or odor step testing your mix.
Batches like this will bleed considerably over time particularly when stored in a plastic container. I would only make what you need for short term needs.
This process is usually done to skunk essence when preparing to use it in a formula or bait. This practice helps in distributing the essence throughout a product more evenly and thoroughly. The oil helps to hold the essence some as well.
Some use this process to allow it to be used more easily on the trapline for example. Such as an LDC or to just squirt it here or there as needed at the set proper. It may also be used to compliment a lure or bait that may have set idle for some time or to just refresh a set a little if your instincts tell you to do so.