The 80/20 argon co2 will work, you just need to ***** your preference for the wine co2 content and its effect on flavor. Most of the time winemakers are talking about degassing the wine to remove the excess co2, and this is fine and necessary to bring the co2 level down to an acceptable range, but it has been shown that, depending on the wine, removing too much co2 can have a negative effect on flavor. Many wineries use gas blends to maintain the desired level of co2 in the wine, but these people have equipment and test methods beyond the scope of most home winemakers.
Below are a couple of clips of some data with references noted. The data is for nitrogen co2 blends, so argon co2 blends will be similar, but not exactly the same. The data is of limited use, because it requires you to know what co2 level you want, but at least it provides a basic understanding of the principles.
"Because CO2 can dissolve in wine and N2 gas can completely deplete the CO2 content in a wine, a mixture of gasses which keep the level of CO2 in the wine constant is preferable. As a rule of thumb the CO2 content in red wines should be below 900 mg/l and that of white wines below 1400 mg/l. A too high or too low CO2 content can be detrimental to the wine ( Peynaud, 1994 ) and the exact level should be determined by taste. From figure 3 the mixture of gases can be determined at different temperatures. A mixture of twenty percent CO2 and 80% nitrogen should be used at 10°C to maintain a CO2 content of 500 mg/l in the wine. So if you consider both the normal cellar temperature and the amount of CO2 needed in the wine, then you can work out the ideal mixture."
See attachment
Figure 3. Theoretical composition of a CO2/N2 mixture to maintain initial CO2 content (Allen, 1994)
"Following Peynaud and other researchers, the ballpark numbers are pretty well known. Wine emerges from fermentation with about two grams per liter of dissolved CO2, and it declines from there. At 500 milligrams per liter, the presence of CO2 is noticeable; at 1,000 mg/L, there is a slight perception of prickliness. The textbook recommendation is that age-worthy reds should be bottled with no more than 100-200 mg/L; light, fruity reds could benefit from about 500 mg/L, and whites, depending on stylistic intent, might range anywhere from 500 mg/L to 1,800 mg/L, from slightly punched up to noticeably spritzy. (Wines & Vines, May 2011)