if you have to, put little white marking tape,but really you need to develop your ear, dont look but listen if you are out
The whole point about the fiddle is that you can play quarter notes if you want to.,you can play beteen f nat and f sharp.
Stringsinger, it is not a question of memorising your positions,its a question of adjusting quickly if youre out of tune,its aquestion of developing your ear,listening[not watching,not trying to do it by measurement],then correcting.
It is also aquestion of temperaments,fretted instruments are generally in equal temperament,a fiddle being fretless,can play in bothe equal temperament and mean temperament,therefore it is more versatile,start sticking frets on it,and youare limiting it to equal temperament.
lastly many fiddlers do not just stick in first position,if they wish to change position,they slide up,most fiddlers would find frets an encumbrance,because they are used to sliding to a new position without being impeded by frets.