Stalled for the time being, as that eldar turret has really taken the wind out of my sails. I've also now started work, so my schedule has been turned upside down and then attacked with a shotgun. On a 4-on/4-off rotation, so hopefully my life will stabilise and I'll be able to use the off-days to get stuff done.
I currently don't convert my files to anything and I try to fix my holes by hand. I also do my best not to create holes. Unfortunately a few of Sketchup's quirks make this impossible at times, and this is part of the reason the Eldar turret is causing such a fuss.
The fellow who was to print and cast my models does minor gap-fixing as part of his service at no extra charge, so wondering if I can get away with sending it his way. He also prints from just about any format under the sun, so not too worried about conversions.