Warming of epoxies can have unexpected results. Slight warming of the individual components makes them flow quicker and measuring is easier, but too warm will make them cure noticably quicker, sometimes very rapidly. That said, for wrap finishes, I usually warm the unmixed parts slightly so they are easier to get out of the bottles. Adhesive epoxies, on the other hand, are very susceptible to heat. Even just mixing too large of a quantity in a small medicine cup will lead to a runaway reaction that causes the epoxy to gel and set rapidly. This occurs even without pre-warming. It is best to mix adhesive epoxy in a puddle on a flat surface so that heat can dissipate and prevent a runaway. I've only had this happen once with finish epoxies when I pre warmed the finish too much, but any warming will cause the finish to set quicker even if there is no runaway reaction. Warming will thin the individual parts and the mixed epoxy for a time, but ultimately thickens the epoxy more and sooner.
A good alternative if you need more working time is to just mix two batches per rod. One for the bottom half of the rod and one for the tip sections. You don't need to mix using 3cc of each (6cc total) component either if you want to conserve finish. I've mixed using as little as 1cc of each with perfect results. That's true of every brand of rod finish I've used. Careful measuring with syringes is all that is needed. With that said I typically use 1.5cc of each part (3cc total)and that is enough for one coat of light build finish on a typical 9ft rod.
The other option is to use a solvent, but this is not novice territory IMO. It's something you definitely need to experiment with and test thoroughly.
