When you build a mill from scratch, you learn a lot. We built a lot of adjustment devices in the design. When I showed my son a brochure, and said we were going to build one, he gave me that "look".
He is an excellent welder and fabricator and still thought I was nutz.
As I stated previously, we ended up using Munks blades and they are as accurate blade after blade, as anything we tried before. The company has no dog in the hunt for selling machines and parts like mill manufacturers. WM sells their own brand of blade and makes money with resharps. They have a stake in how they teach their customers.
My point is, a 19" band wheel is stressing the blade in the tight radius. They have NO give at the wheels.
We used trailer hubs and tires. The rubber tire HAS give, so shock absorption is a non issue. We use Cooks roller blade guide system. Works well with lots of adjustment capability. We don't "stretch" our blades, the tires allow for knots, clumps of bark, and, if paying attention, you "hear-feel when something is going wrong and shut down to investigate.
Cooks recommend their blade roller, to take the curved "set" out of a used blade, after using on hard "steel" wheels. I don't know anything about Cooks mills. We could not afford to buy a mill at the time we needed one. After several years, Cooks, WM, TK ,etc are still in business, so, I believe they make good equipment.
As far as "pre set", we still watch the blade as we run up the RPM's, and, if it runs a little toward or away from the roller guide flanges, we adjust accordingly. We run our mill by "feel" watching how it performs, like operating a bull dozer. There are no levels or other handy devices on dozers. You climb on, do the deed and watch how it comes out, adjusting as needed. Actually, we have 2 adjustment bolts, one for tension, the other for blade travel on the guide rollers.
At an agri show, in Moultrie, Georgia, Dave Mann, head honcho for Wood Mizer, heard me discussing how I changed one of their features when we built our mill. He was talking to a crowd, and, as we turned to leave, he asked us to hang on a minute. He had guessed we were the ones that built an open sided cantilevered mill, like WM's. I was ready to hear about copyright infringements, as we had heard from many people, because we copied the WM design. Actually, he was interested in what we said and asked several questions about what and why we built the cantilever design. I told him, and, he wished us good luck with the mill.
I bought a used Peterson Swing blade mill for down here, to cut BIG-hard logs. I had asked a lot of questions on another forum, and got feedback from Peterson when I talked about building a swing mill. I was even invited to visit their factory, in New Zealand, by one of the owners, and was told I would have access to their "design-research" room. Apparently, they like free thinkers that try different ideas.
My son took over the sawing when I moved down here, but, he just didn't catch on to the whole reading the log, getting the most out of it, and, he was working alone. Our mill was set up for 2 people system as I did the sawing and Ed did the heavy work. Kirk and Buzz actually saw the mill in action.
If this comes across as bragging, or, being an expert, it is NOT my intention. I just call 'em as I see 'em, and always try to help anyone that asks questions. I just pay close attention and keep the blade in the log, rather than worry about a few pounds of blade tension. All my concerns were worked out on the build(s) of 2 mills. I was told by many people that we could not build a functioning mill and we could NEVER keep a blade from running off a mill.
Have y'all read the thread where I taught a complete stranger, online, how to sharpen blades AND change the profile? Sawmill Squaw was the student and she is married to a hard headed guy. She did what I explained and her husband bragged all over their area of how she did a better job than the ones they tried at getting their blades sharpened. She simply paid attention and asked questions, same as y'all here.
This is why I asked for input and to keep things civil. Blade tension is not some magic trick. Just find what works for YOU and keep doing it.