Pamster, please read here: https://www.fairtrading.nsw.gov.au/Factsheet_print/Tenants_and_home_owners/Strata_schemes/The_owners_corporation/FTR47_Sinking_funds.pdf
The formula is the 10 year plan. Ours is a small strata like yours. A 10 year plan is easily done by anyone with a bit of spreadsheet knowledge.
We have put into the plan: the things that need doing; their estimated cost; the total of sinking fund levys and the running balance of the Sinking fund (Capital works budget).
The spreadsheet will give you an idea whether the strata has put enough away for capital works.