That's not that far from the current 5.5:1.
A 6.25:1 ratio just means there is a bit more resin, it has been my experience that epoxies in general are pretty forgiving with the mix ratios, maybe who ever makes ProLine found, a hotter mix gives better working properties.
That's not correct.
If you are using a professional epoxy system, your need to pay attention to the manufacturer's mixing ratios if you want the specified properties of the resin. Many high strength resins have 4 reacitive sites per molecuile and may linkers have 2 per molecule, so ideally the epoxy mixture should have 2 linker molecules for every resin molecule to make a perfect polymer.
Since the ratio of resin molecules to linker molecules is determined with chemistry, if you use a higher numerical ratio (not enough linker) not all the bonding sites on the resin won't be used. If you use a lower numerical ratio (not enough resin) all the bonding sites on the linker won't be used.
Either way the resulting epoxy polymer will be weaker than expected. You don't want o be off by more than a couple per cent on the ratio.
You can purchase a 1 kg digital scale with a 0.1 g resolution for not more than $15. HarborFreight is one source and they are all over Amazon. You can use disposal plastic cups to mix. Take the cup you are goin to mix in and tare it on the balance and then pour in the approximate amount of liiner you need (the smaller quantity) and write down the weight. Tare the balance. You need add the ratio tiem the linker weigh to the linker. A trick is to use a second cup and pour out a few percert more resin than you need into it, and then pour from it into the linker container. The viscosity if the resin will cause the flow to so as you near the ideal mixture and it is easy to get within +/- 0.2 g of your target. As long as you were planning to use 10+ g of resin, your error is less than 2%. If your adding a filler, do it last. Then mix, mix, mix. Use popsicle sticks or tounge depresssors to stir the mix. When you think your done, continue, and by the third time you think your done, you are, but never less than a minute.
Always wear nitrile, pvc, polyethelene or buna rubber gloves. This keeps the resins off your skin and your finger prints off the materials your going to epoxy together. Epoxies do not form chemical bonds to cure resins or compiosites. All bonding is mechanical on the molecular level, so sand surfaces with relatively coarse paper before appling the epoxy to enchance the bonding.
Bob