Dynamic Components look interesting. However as a (very) lean startup for now I can’t afford the Pro license. :^(
I hear what you say about scale. However the inconvenient truth is that for my more recent designs I have been modelling a product which is in millimeters in whole metres - and still getting problems. Hmm… I think I need a real solid modeler.
Fwiw, I didn’t get on with Autodesk’s 123D Design so I am now trialing their Fusion 360 instead which is probably overkill for my requirements however you get the full caffeine version for free if you are any of: “for students, enthusiasts, hobbyists, and startups…” “for as long as you need it”.
Note that the free version of SketchUp can only be used at home for a hobby. For things you use for work, prepare to pay. Most of the really “free” software has so severe handicaps that usually to rely your business on them is a waste of time.
In addition to the ones you are trialling, have you taken a look at Rhinoceros? It’s more expensive than SketchUp, perhaps more suitable for small engineering-type things, but the interface is IMO not as “intuitive”.
We would need to see the model to understand how you are getting holes. That doesn’t need to happen.
Back when Google owned SU, anyone could use the free version for business. That changed after the sale to Trimble and the release of SU13. The help center only offers downloads back to SU13. So if you could get SU8, you could use SU for business - The latest and greatest SU STL export plugin can be installed in SU8 (one of the advantages of using extensions for important functions…)
I can see girds as being useful in Sketchup - if they were optional and adjustable. For example, in the construction industry and therefore architecture there has long been a tradition of using grids to establish critical reference points or to encourage the designer to work with standard building material sizes. Long before CAD came along building designers often used gridded paper or underlays to simplify the process of building layouts. In housing, wall studs and subassemblies were typically at 16" or 24" on center.
Why would you assume that someone who thought that might be a good idea had failed to “teach yourself the program”?