While researching tire size options, I found the below website to be very helpful in comparing sizes against each other, and against stock. Given that final gearing, rpm at various speeds depends directly on the diameter, in my case it was important to stay as close to 26 inches in diameter as possible (diameter of Monte SS stock 215/65r15). It also helped me plan for any tire rub, as well as to not accidently go smaller in diameter, such as when considering 245/40r18.
https://www.tacomaworld.com/tirecalc?tires=235
Today I had my set of 235/45r18 (0.3 in larger overall diameter) tires mounted on some BMW forged wheels, which I had machined to match our bolt pattern. Front and rear I have 3mm and 8mm spacers, and so far they look good. In the garage at least!
Thanks again for all the suggestions.