First off, I understand the racing requirement for non glycol coolants. You probably dropped the Evans idea because Evans happens to be 100% glycol / propylene glycol / ethylene glycol depending on the particular Evans product. Clearly, the Evans product fails the no glycol rule. Distilled water with Water Wetter or whatever anti corrosion package you want is the way you have to go. Pure water will also provide superior heat transfer from the engine.
The Evans product is designed as 100% glycol base. Evans notes that the product has a very high boiling point (> 375 F) which is why they can probably make the claim that it eliminates boil overs. The very high boiling point has the rather nasty side effect of reducing nucleate boiling in the head (nucleate boiling is desirable) which is critical to getting good heat transfer from the head metal to the cooling fluid. When you purchase conventional non premix engine coolants, if you carefully read the fine print on the back they typically recommend against exceeding a coolant / water concentration of 60%. Higher glycol concentrations elevate the boiling point. This may reduce or eliminate boil over; but, has the perverse effect of elevating the head metal temperature at the same time. The B18 and B20 engines with high compression ratios are already detonation prone and elevating the head metal temperatures is the last place you want to go. You can read here about the effect of Evans Coolant on head temperatures
https://www.norosion.com/evanstest.h...0be%20achieved.
Note the impact on required octane rating. Also note the effect of the elevated head temperature on valve recession on engines that have not had hardened valve seats installed.
Higher water concentration will improve heat transfer away from the engine; which should reduce head metal temperatures; but, the higher water concentration also drops the boiling point so you may increase the risk of boil over if your radiator is impaired by scale or corrosion and you can't get rid of that heat. If you suffer from boil overs Evans Coolant might eliminate the boil over problem; but, have other negative effects. My preference would be to address the cause of the boil over rather than hide it by using Evans Coolant.
Being 100% glycol base, the Evans product should eliminate corrosion issues.
My preference is go with a conventional coolant mixed with distilled water and use the highest water % permissible for the expected temperatures (don't want to crack the radiator by having the coolant freeze) in line with the guidance on the labels. The high water content insures good heat transfer from the head. Flush and replace the coolant every 5 years to make sure the corrosion inhibitors remain active.