You use "tick" and "tock" alternating. My suggestion is to introduce another parameter "bar". It should be able to take values 2-13. Have the "tick" only on beat 1 for every bar, e.g.:

Bar=2 tick tock tick tock ....
Bar=3 tick tock tock tick tock tock ...
Bar=4 tick tock tock tock tick tock tock tock ....

etc..

The rationale is that any "bar" has some "inner structure". For instance a 4/4 bar is not just a sequence of 4 equal beats but in fact the first and third beats are stronger than 2 and 4 and 1 is even stronger than 3. For this reason "3/4" and "6/8" may look like the same fracture but in fact the beats are sounding quite differently (when higher numbers denote more stress on a beat 3/4 is "2 1 1 2 1 1 ..." whereas 6/8 is usually "3 1 1 2 1 1 3 1 1 2 1 1 ...". It makes sense to help the user of the metronome recognize the 1-beat (usually the stroke with the most significance) in every bar by making it sound differently.

Why 2-13: the longest metrum of any significance in practical music is 13/8, used for instance in "Blue Rondo à la Turk" by the Dave Brubeck Quartet (it is sometimes denoted as 9/8 // 4/4 alternating metrum, but i think it is a genuine 13-stroke bar structure). 12/8 is commonly used for slow Blues with the "triplet shuffle" feeling,

I hope this helps.

bakunin