I like your test stand. I've already started one using recirculating ball type linear guides and four receivers. Using a seriously high end high end load cell and an Omega DP87 Strain Gage Indicator. I will of course post pics as I go. I really like the engine mounts to the base on yours. Do you have slotted holes between the L-Bracket and Base for width adjustment? When I started I was shopping for similar digital scales but the accurate units were pricy. I picked up all of the hardware on eBay, guides, load cell and indicator. I would think It depends on the sampling rate of the indicator if you have a lot of harmonics. Do you have a lot of variations on the readings with this engine? I was going to dampen some harmonics with an elastomeric coupling between the sled and the load cell to dampen ghosting due to the sampling rate of the indicator and the harmonics of the engine. I have designed the one I am working on to read in both directions, push and pull.