Ben, We have had problems using accelerators in single part paints and varnishes since they tend to cause early crazing and failure of the finish. As far as paint viscosity, in general I have found that we always need to thin single part Marine enamels which includes the Interlux Brightsides. I normally thin until the last of the flow off of a paint stick breaks into drops rather than being a continuous flow. It is better to apply these types of coatings in thinner coats and apply more of them since thick coatings don't cure properly. I have found that it usually takes 3 coats of the Brightsides to fully cover the substrate though this is when working on vertical surfaces such as hulls and coverage is likely to be better on horizontal surfaces. I cannot comment on the deck stripping tool since I have never used it but I am sure that you will get the input that you need from the experts here. Best of luck.
Not sure about accelerator but maybe a possibility. I am using tool improperly per your comments. I'm holding it closer to vertical than horizontal. This is causing paint to drip out. I'll try technique you suggest. Also per Dave I may leave can open a while covered with mesh to allow some evaporation which will thicken paint.
I am not sure you need to thicken the paint. It sounds like you need less of it on the application wheel. Are you using the tool so the barrel stays below the wheel? The tool should not be used upright. Ideally when using a pinstripe tool you want to illuminate as much gravity as you can. This will put less paint on the wheel. Also, if you put the non-paint end of the tool in the groove on the deck, it will help keep your line straight as you pull/push the tool to apply paint. Try this technique on a some paper first, it may be all you need.
It's time to repaint my stripes. I'm using an available interlux poly-urethane paint. My problem is paint is too thin and dripping from roller on striper. Can anyone recommend a thickening agent? Current mixture is 50/50 Interlux Brightside single part enamel and Interlux flattening agent. All suggestions welcome.