Wow a contrast in water temperatures to go home to!
Kuta to the Tromso surf coast, I would consider something 8ft o 8ft 6‘‘ but I suggest buying the board in Europe, Airlines can charge dearly for transporting Surfboards and the longer to more costly and they can treat surfboard badly in transit.
There are many very good surfboards brands available, one brand you can try in Bali and buy in Europe are the Torq boards.
There are good shapers in Bali but there’re quite a few Junk boards too, good for one season and then dead.
A thought to consider, in Bali with the great weather, board shorts and anti sun sun and rash shirt paddling is easier, Norway, paddling through your wetsuit much harder so a long board makes some of the difference.
BTW the Mini mal shape is a great shape to learn on! Try hiring a number of boards with different lengths, it will give some insight!
HEY and severely less crowds in Norway
You are going in the shoulder season to Bali, so the surf may be a little less dramatic,
If you are considering buy post a picture here first and we will help you choose, and we have several forum members in Bali who might give you further advice
Have a great time,

Just did a browse for Norwegian surf board shapers, there are 4 companies that look good even an Australian shaper ( i looked at their catalogs)
Adhd surfboards, Frost surfboards, Infusion surfboards and Lofoten surf centre .
Have browse before you go!
I've taken up troll hunting just for fun, instead of a rifle I'll just use a pun! 冲浪爷爷