That depends: getting out of elective gavelkind requires to go feudal and you might not want to rush that too much as the transition leaves your weak. Staying tribal for several generations have its perks (prestige building etc). Also if you want to reform you might not be able to do so in one generation (unless you are very experienced or use one of the really good starts).
If well managed elective gavelkind is not as bad as it is made out to be. Yes, you cannot gather a large personal real at the same times have a lot of sons. But starting as Norse you have plenty of opportunities to expand - leaving lands for your other sons (unless you have alot of sons). Of course kingdom tier titles will break off if they can (I assume a kingdom is formed during the life of the first ruler). Trying not to expand in any direction on full kingdom is a plan: as Sweden take only half of Finland, some of Norway, some of Denmark etc (similar for the other realms). Especially along the Baltic coast is a lot of nice duchies to gather, that wont force you to create a second Kingdom. Then wait for the de jure drift before taking more land in any direction. Alternatively wait only until a few short wars will get you the empire title.
If a kingdom size realm breaks away, you are one war/murder away from uniting your realm (dont merry sons you dont want to rule, or better yet merry them off to old women in your court for safety, so they dont elope or do other stupid things).
In Rssia forming either Ruthenai or the other kingom, leaves you with plenty of expansion posibilities without the probem of whole parts of the real breaking away. I never had any problems in this direction.
In most cases i havnt had any problems.
I gavelkind is too much of a problem: dont have sons. This is an alternative strategy, have sons in the first generation and land as many as possible, and then after the first generation stop having more sons (merry old women). The dynasty should be big enough to create enough legitimite heirs and you can selct between them as your successor. If landed this brings more counties into your realms, so I have had to shift between son-less rulers and rulers with sons to split it up again.