As Doug mentioned you can mix it by ounce but 5oz. of product is a lot to waste. Try the following:
1 part DG 601:4 parts DG 501 or 1/4oz. of DG 601:2oz. DG 501 (same ratio for using DG 105 or DG 111)
Large plastic syringes will work so that you can mix even less if needed. Just remember that you will want to only do 1 part DG 601 polish bonding agent. If this becomes troublesome just apply DG 601 straight to the paint then layer DG 501 or 105 or 111 right on top without wiping away DG 601. Pre-mixing saves time and allows you to apply 1 product right away instead of 2. Does this help?
DG 501 has more chemical cleaners than 105 but I can't comment on exactly how much more protective properties one has over the other. In my opinion if you know you have clean paint then you can use DG 111 without issue. In my experience DG 105 is less temperamental with humidity than DG 111 can be.
Products discussed:
DG 601 - Polish Bonding Agent
DG 501 - Marine/RV Polish
DG 105 - Total Performance Polish
DG 111 - Clear Coat Polish