This sounds like a piece of cake for a fab house.

Aspect ratio would be 4.43:1 based on a .021 drill size - this is the
size drill I would use if I fab'd the board. (If annular ring was OK).

Current technology can plate upto 9+:1.  I know, were I work, we have
built 7.3:1 on a .106 thick 8 layer rigid PCB (2+ years ago).

Questions to ask: Be blunt, ask "What is the maximum aspect ratio you
can plate reliably?"  No board house would agree to build a board they
know will have excessive fallout or significant plating problems in
there shop.

The above comments are my own and not of my employer.

Joe Duclos - Tooling Engineer
ECC Corp
156 Princeton Street
Holden, MA 01520

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