A gelatinization rest at 149F for 15 minutes won't do too much regarding gelatinization. Although, gelatinization/dextrinization takes place at 149F it actually begins around 133/135F and continues up to denature. When an infusion method is used with a mash temperature of 149F it takes about 4 hours of constant temperature with a single enzyme to cause gelatinization and for the enzyme to produce enough Limit Dextrin to improve stability of the final product. Mash is boiled for a reason. Without boiling the mash amylo-pectin doesn't enter into solution at an appropriate level. The beer will lack body due to wort lacking in Limit Dextrin. .