Nice find, very interesting that you know about sealing mk10s before you started diving
I’m in the EU so can’t recommend a place to service it at; but your cost estimate seem about right
The tricky part— finding the SPEC boot (black silicone ring without the ambient holes) that is used for sealing, they have been discontinued
(I do have some SPEC boots in storage and would share, let ne know if you don’t find a closer source to avoid cross-Atlantic shipping)
And the cost of the lube on top of xourse (around 2Oz); the „proper“ way now is Cristolube or Tribolube which costs more, some DIY users still fill with silicone (cheaper)
I would go with 2 G250s ( having 2 identical 2nd stages), wouldn’t bother with having a „yellow octopus“
It’s a preference thing
(i also have spare g250s if you can’t source locally, I would even send it serviced — again last resort due to shipping and possibly tariff costs)
DIY service is a great idea, but of course at your own pace
E2A: I just realized that for service and also learning DIY you might wanna reach out to
@rsingler (His reg tech class did wonders for me, and I was servicing mk10/g250 as well in class)