Enlargement exposure (ie the time you expose your negative to the paper) is dependant on many variables.. so quoting 10sec @ f8 is somewhat irrelavent other than you can use that info to start your test strip test. What everyone has said about test strips is appopiate however, and you'll probably find you'll do a test strip or two per print until you can look at the 'proof sheet' (did you do one of these?) and guess slight variations that a print may require (or the effect you wish - give the same negative to several printers and they all might interpret it differently)(posted 8857 days ago)So... do what Scott says and see how you go. If the test strip is still too dark, you may have to decrease the power of your enlarger globe as print times can be too short to perform and manipulation (dodgeing and burnning) and you don't want to stop the lense down any more. The other thing that you didn't mention is the print size... Bigger prints need more time and I have a problem making little prints (for family albums) occasionly.
As Anna mentioned, at this stage of your career, the processing times (developer, stop, fixer and wash) should stay consistant as advised by the manufacturers instructions. Some people (not me) do use developers where the time and dilution is changed to obtain varying results, however I suggest you stick with what your doing.